vvEPA
United States
Environmental Protection
Agency
EPA/600/R-15-301 | May 2016
www.epa.gov/homeland-security-research
Feasibility of Selected Infectious Carcass
Pretreatment Technologies
Bioneduction
Digestion
Burning
Burial
Alkaline
Hydrolysis
Sterilization
Size Reduction
Landfill
Carcass Pretreatment
and Management
Options
Packaging
Rendering
Incineration
Freezing
Encapsulation
Physical Inactivation
Additives/ Sorbents
Chemical Inactivation
1 J
Office of Research and Development
National Homeland Security Research Center
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Feasibility of Selected Infectious Carcass Pretreatment Technologies
U.S. Environmental Protection Agency
Office of Research and Development
National Homeland Security Research Center
26 W. Martin Luther King Drive
Cincinnati, OH 45268
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
DISCLAIMER
The United States Environmental Protection Agency through its Office
of Research and Development managed the research described here
under Interagency Agreement No. RW-70-95849301 with the
Department of Homeland Security. The report was developed by Tetra
Tech under contract EPC11037 Task Order 10. It has been subjected
to the Agency's review and has been approved for publication. Note
that approval does not signify that the contents necessarily reflect the
views of the Agency. Mention of trade names, products, or services
does not convey official EPA approval, endorsement, or
recommendation.
Questions concerning this document or its application should be
addressed to:
Sandip Chattopadhyay, Ph.D.
U.S. Environmental Protection Agency
National Homeland Security Research Center
26 West Martin Luther King Drive, Mail Code NG16,
Cincinnati, Ohio 45268
513-569-7549
Chattopadhyay.sandip@epa.gov
Paul Lemieux, Ph.D.
U.S. Environmental Protection Agency
National Homeland Security Research Center
109 T.W. Alexander Drive, Mail Code E343-06,
Research Triangle Park, NC 27711
919-541-0962
Lemieux.paul@epa.gov
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Acknowledgments
This technical report has been prepared for the United States Environmental Protection Agency
(U.S. EPA) Office of Research and Development (ORD), National Homeland Security Research
Center (NHSRC) and U.S. Department of Agriculture (USDA), the Animal and Plant Health
Inspection Service (APHIS)/ Department of Homeland Security (DHS), Science and Technology
Directorate. Dr. Paul Lemieux of NHSRC, Research Triangle Park, North Carolina, served as
task order contracting officer representative. APHIS guidance, reviews, and comments were
provided by Lori P. Miller, PE. Dr. Sandip Chattopadhyay (NHSRC) served as the lead author.
DHS review and comments were provided by Michelle M. Colby and Aileen Mooney. We also
acknowledge Mario Lerardi of EPA's Office of Resource Conservation and Recovery for his
insightful comments.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table of Contents
DISCLAIMER i
Acknowledgments i i
Table of Contents iii
Acronyms and Abbreviations vi
Glossary ix
Executive Summary 1
1.0 Introduction 3
1.1 Purpose and Scope 3
1.2 Analysis of Existing Data and Quality Assurance 4
1.3 Inventory of Large Animals 5
1.4 Selected Pretreatment: Size Reduction, Physical and Chemical Inactivation 8
1.4.1 Homogenization 9
1.4.2 Separation 9
1.4.3 Size Reduction 10
1.4.4 Inactivation 13
1.4.5 On-Site or Off-Site Treatment/Disposal 13
1.4.6 Activity Prior to Transport of Carcasses 13
2.0 Evaluation of Individual Alternatives 15
2.1 On-site Size Reduction 15
2.1.1 Effectiveness 22
2.1.2 Impact on Environment 22
2.1.3 Implementability 25
2.1.4 Reduction in Toxicity, Mobility, or Volume through Treatment 30
2.1.5 Cost 31
2.1.6 Regulatory Issues 34
2.1.7 Personnel Safety 37
2.1.8 Community Acceptance 40
2.2 Physical Inactivation 41
2.2.1 Effectiveness 41
2.2.2 Impact on Environment 44
2.2.3 Implementability 45
2.2.4 Reduction in Toxicity, Mobility, or Volume through Treatment 45
2.2.5 Cost 45
2.2.6 Regulatory Issues 48
2.2.7 Personnel Safety 49
2.2.8 Community Acceptance 49
2.3 Chemical Inactivation 49
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.3.1 Effectiveness 50
2.3.2 Impact on the Environment 55
2.3.3 Implementability 56
2.3.4 Control Measures for Chemical Inactivation Agents 67
2.3.5 Cost 68
2.3.6 Regulatory Issues 68
2.3.7 Personnel Safety 69
2.3.8 Community Acceptance 70
2.4 Combined Physical and Chemical Inactivation 70
3.0 Analysis of Pretreatment Technology Alternatives 72
4.0 Summary 76
5.0 References 77
List of Tables
Table 1. Cattle Inventory by Class - States and United States: 2015 6
Table 2. Conversion of Animal Volume and Mass by Species 8
Table 3. Carcass Pretreatment Options Matrix 9
Table 4. Size Reduction System Manufacturers, Type and Capacity 11
Table 5. Advantages and Disadvantages of Shredder, Crusher, and Grinder 15
Table 6. Types of Size Reduction Equipment 20
Table 7. Recommended Distances by Selected Agencies 23
Table 8. Assessment Methods for Microorganisms in Bioaerosol Samples 26
Table 9. Bioaerosol Control Strategies and Technologies 29
Table 10. Impact on Air, Water, Land, and Energy by Rendering 31
Table 11. Representative Hourly Cost Breakdown of Tub Grinder Operation 32
Table 12. Representative Hourly Cost Breakdown of Chipper and Hammermill Operation 33
Table 13. Estimated Cost of Fixed Plant and Mobile Unit 34
Table 14. Examples of Local Carcass Management Regulatory Issues 35
Table 15. Costs of Selected Physical Inactivation Pretreatment Technologies for Carcasses..46
Table 16. Influence of Chemical Inactivation Agents on Pathogens in Carcasses 52
Table 17. Ranking Susceptibility of Pathogens in Carcasses 53
Table 18. Etiology of Animal Prion Diseases and Typical Inactivation of Prions 54
Table 19. Characteristics and Considerations for Selected Chemical Inactivation Agents 58
Table 20. Selected Viral Families, Virus and Species Affected 59
Table 21. Properties of Ideal Chemical Inactivation Agent 65
Table 22. Comparison of Costs and Other Criteria of Representative Chemical Inactivation
Technologies 68
Table 23. Comparison of Pretreatment Technologies and Overall Ranking against Various
Carcass Management Options 75
List of Figures
Figure E-1. Key Pretreatments of Infectious Carcasses Prior to Carcass Management
Processes 1
Figure 1. Cattle Farms and Federally Inspected Cattle Slaughter Plants (left) and Cattle
Inventory (right) across the U.S. (modified after Gwin and Thiboumery, 2013) 7
Figure 2. Stress and Strain Relationship: The modulus of elasticity is low for soft materials and
high for hard materials 19
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Figure 3. Examples of Robot Integrated Sensors that Could be Adapted to Carcass Handling
and Processing Tasks 40
Figure 4. A normal prion (left) and a disease-causing prion (right) 53
Figure 5. Criteria Evaluated for Selected Carcass Pretreatment Technologies 72
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Acronyms and Abbreviations
°C degree(s) Celsius
A avian
ABP Animal By-Product
APHIS Animal and Plant Health Inspection Service
ATCC American Type Culture Collection
AU Animal Unit
AVMA American Veterinary Medical Association
B bovine
BAT best available technique
BLV Bovine leukemia virus
BOD biological oxygen demand
BRSV Bovine respiratory syncytial virus
BSE bovine spongiform encephalopathy
Bt bat
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
cfm cubic feet per minute
CFR Code of Federal Regulations
CH3CO3H Peracetic Acid
CI02 Chlorine dioxide
C02 Carbon dioxide
COD chemical oxygen demand
Cp Caprine
Cv cervine
CWD chronic wasting disease
DHS Department of Homeland Security
DS double stranded
dSV discounted salvage value
EB Enterobacteriaceae
EC European Commission
EEE Eastern equine encephalitis
EFSA European Food Safety Authority
EIA Equine infectious anemia virus
ELISA enzyme-linked immunosorbent assay
EOC Emergency Operations Center
EPA U.S. Environmental Protection Agency
EPCRA Emergency Planning and Community Right-to-Know Act
EPS extracellular polysaccharide
Eq Equine
ELI European Union
EUSE exotic ungulate spongiform encephalopathy
fc Crushing strength
FAD Foreign Animal Disease
FAO Food and Agriculture Organization
FDA Food and Drug Administration
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
FeLV Feline leukemia virus
FIV Feline immunodeficiency virus
FMD foot-and-mouth disease
FOB Freight on Board
Fr Ferret
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
FSE Feline spongiform encephalopathy
GAO Government Accountability Office
GC/MS gas chromatography/mass spectrometry
h hour(s)
ha annual hours of use
HEPA high-efficiency particulate arrestance
HIV Human immunodeficiency viruses
HPAI highly pathogenic avian influenza
hp horsepower
HPLC high performance liquid chromatography
HSPDs Homeland Security Presidential Directives
1 interest rate
IHN Infectious hematopoietic necrosis
IPN infectious pancreatic necrosis
IPPC Integrated Pollution Prevention and Control
Kk Kick's constant
Kr Rettinger's constant
kOU kilo odor unit
kg kilogram(s)
kW kilowatt(s)
lb pound(s)
L Lagomorph
L liter(s)
U initial dimensions of particle
L2 final dimensions of particle
LAL Limulus amebocyte lysate
LPS lipopolysaccharide
m3 cubic meter(s)
MeV megaelectron volt
mtDNA mitochondrial DNA
mVOCs microbial volatile organic compounds
n years of life
NA not applicable
NABC National Agricultural Biosecurity Council
NaBr Sodium Bromide
NaOCI Sodium hypochlorite
NaOH Sodium hydroxide
NASS National Agricultural Statistics Service
NCRWQCB North Coast Regional Water Quality Control Board
NHSRC EPA National Homeland Security Research Center
NIOSH National Institute for Occupational Safety and Health
NH3 Ammonia
NHP non-human primates
NOx oxides of nitrogen
NPDES National Pollutant Discharge Elimination System
NPT National Pipe Thread
O Ovine
02 oxygen
03 ozone
OSHA Occupational Safety and Health Administration
OU odor unit
OU/s odor unit per second
vii
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
ORD
Office of Research and Development
PCR
polymerase chain reaction
P
Porcine
Pb
Lead
PLC
programmable logic controller
POTW
Publicly Owned Treatment Works
PP
Purchase Price
PPE
personal protective equipment
PrP
prion protein
QA
Quality Assurance
QAC
Quaternary Ammonium Compound
QAPP
Quality Assurance Project Plan
R
size reduction ratio
R
Rodent
RCRA
Resource Conservation and Recovery Act
READEO
Regional Emergency Animal Disease Eradication Organization
RIA
radioimmunoassay
RPM
revolution(s) per minute
Sc
scrapie
SCAQMD
South Coast Air Quality Management District
SDS
Safety Data Sheet
SRM
specified risk material
SS
single stranded
STAATT
State and Territorial Association on Alternative Treatment Technologies
TDE
transmissible degenerative encephalopathy
TCLP
Toxicity Characteristic Leaching Procedure
TGE
Transmissible gastroenteritis
TLC
thin layer chromatography
TME
Transmissible mink encephalopathy
TSE
transmissible spongiform encephalopathy
TSS
total suspended solids
TVC
total viable counts
U.S.
United States
UNEP
United Nations Environment Programme
USDA
United States Department of Agriculture
UV
ultraviolet
VAC
Volts alternating current
VEE
Venezuelan equine encephalitis
W
Rettinger's energy
Wi
Bond work index
WEE
Western equine encephalitis
WNV
West Nile Virus
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Glossary
Disposal: The discharge, deposit, injection, dumping, spilling, leaking, or placing of any solid or
hazardous waste on or in the land or water. A disposal facility is any site where hazardous
waste is intentionally placed and where the waste will remain after a Treatment, Storage or
Disposal Facility (TSDF) stops operation.
Pretreatment: Any method, technique, or process designed to physically, chemically, or
biologically change the nature of a waste for the purposes of facilitating subsequent additional
treatment activities and/or final disposal.
Treatment: Any method, technique, or process designed to physically, chemically, or
biologically change the nature of a waste.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Executive Summary
The challenge associated with the management of animal carcasses includes protection of
environmental, animal, and public health against potential microbiological threats. An animal
carcass is composed of microbiologically active material that may contain viruses, bacteria,
protozoa, parasites, prions, toxins, drug residues, and other chemicals. All of the biologically
active materials need to be reduced to safe amounts, eliminated, or sequestered to minimize
their potential hazard. The management of animal carcasses varies between and within states,
and, depending upon how the carcasses are managed, may need to consider both federal and
state environmental requirements. Pretreatment of infectious carcasses may be suggested by
the carcass management decision makers to improve the operation of the mechanical
components of the downstream process equipment and/or to minimize potential biological or
physical effects of the carcass management processes. The type of pretreatment will vary
according to type of feedstock used, the potential level and type of contamination, feedstock
size, the carcass management process to be used, and the desired quality of the end-product.
U.S. EPA (2015) identified eleven infectious carcass pretreatment technologies and screened
them to describe how each technology can be used prior to, and in conjunction with, the six
large-scale carcass management options (Figure E-1).
Bioreduction
Digestion
Alkaline
Hydrolysis
Burning
Burial
Steri hzation
Size Reduction
Landfill
Carcass Pretreatment
and Management
Options
Packaging
Rendering
Incineration
breezing
Encapsulation
Physical Inactivation
Additives/ Sorbents
Chemical Inactivation
Figure E-1. Key Pretreatments of Infectious Carcasses Prior to Carcass Management
Processes.
The six carcass management options considered were: (i) rendering, (ii) burial, (iii) landfill, (iv)
composting, (v) incineration, and (vi) burning. These carcass management options require
specialized equipment, accessories, and other resources and appropriate geologic, hydrologic,
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
and climatic conditions. The eleven carcass pretreatment technologies identified and screened
were: a) on-site size reduction, b) digestion, c) bioreduction, d) alkaline hydrolysis, e)
sterilization, f) freezing, g) physical inactivation, h) chemical inactivation, i) additives/sorbents, j)
encapsulation, and k) packaging (U.S. EPA, 2016). The emerging or evolving technologies
(such as gasification, plasma technology, irradiation, thermal depolymerization, dehydration,
and extrusion) for treatment of carcasses were not included within the eleven pretreatment
alternatives as these technologies are in research stage and need additional testing and
evaluation. All technologies have strengths and weaknesses. Based on the critical evaluation
of eleven infectious carcass pretreatments, three technologies (size reduction, physical
inactivation and chemical inactivation) were shortlisted for additional analysis in this report.
Animal carcasses considered in this report include whole bodies or body parts of dead animals
that may be mixed with manure and bedding or other organic materials that cannot be
separated from the animal carcasses. Regulatory issues concerning carcass management vary
from state to state, and the treatment and disposal may require special permit(s) approved by
one or more state agencies, the United States Department of Agriculture (USDA), and the local
health department depending on the state of origin of the material.
Each of these three shortlisted pretreatment technologies was defined and evaluated based on
effectiveness, impact on environment, implementability (including ease of use, portability, and
throughput capacity), reduction in toxicity, mobility, or volume through treatment, cost,
regulatory issues, personnel safety and community acceptance. As identified in Homeland
Security Presidential Directives (HSPDs) on Defense of United States Agriculture and Food and
Biodefense for the 21st Century, mechanisms for protection of critical infrastructure are
fundamental components as part of any comprehensive strategy for biodefense. Focused
development and deployment of technologies to foster proactive protection, response and
recovery is necessary to protect against any significant infectious disease threat. In the case of
high-consequence livestock pathogens, these technologies play a crucial role in the
preventative, mitigation and recovery phases of an outbreak. It is crucial to select a
pretreatment coupled with an appropriate carcass management technology that encompasses a
strategic framework dealing with infectious carcass management to ensure that the maximum
environmental, occupational safety, and economic benefits of the technologies can be achieved.
The elements of a strategic framework include waste minimization; segregation; developing a
safe and effective collection, transport, and storage system; waste management and
contingency planning; protecting the health and safety of workers; and proper siting of the
treatment technology. The most feasible pretreatment options identified in this study which can
be applied singly or in combination prior to the routine and catastrophic management of
infectious carcasses includes size reduction and physical and chemical inactivation. If more
than one inactivation treatment should be applied to carcasses, the combined microbiological
reduction effect might be greater than the effect of one treatment alone. Methods, strategies,
and practical applications presented in this report describe acceptable means for treatment of
carcasses prior to a given carcass management process. Each treatment has its advantages
and disadvantages as costs and benefits. The actual decision on which treatment or
combination of treatments are suitable should be based on individual circumstances and the
applicable federal, state and local restrictions.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
1.0 Introduction
1.1 Purpose and Scope
More than 40 contagious foreign animal diseases are recognized as threats to the U.S.
agricultural economy (GAO, 2003). Agriculture is the largest industry and employer in the
United States, generating more than $1 trillion in economic activity annually, including more
than $50 billion in exports. U.S. agriculture is threatened by the entry of foreign pests and
pathogens that could harm the economy, the environment, plant and animal health, and public
health (GAO, 2005). A key component of this economy is the livestock industry, which
contributes over $100 billion annually to the gross domestic product (GAO, 2005a). Diseases
affecting livestock could have significant impacts on the U.S. economy and consumer
confidence in the food supply. The introduction of animal and plant diseases at the farm level
would cause severe economic disruption, given that agriculture accounts for 13% of the U.S.
gross domestic product and 18% of domestic employment (DHS, 2008). Spread of animal
diseases has a multicausal origin. Some factors associated with this process include: a)
agroterrorism, b) trade and international travel (increased frequency and speed of local and
international travel, fostered by the globalization process promotes the spread of
microorganisms on a global scale), c) changes in agricultural practices (animal domestication
was one of the main promoters of microbial evolution by facilitating the availability of new
susceptible hosts at high densities due to the intensification of livestock systems), d) climate
change (which causes changes in the eco-geographical distribution of vectors), e) reduction of
habitat and increased contact with wild vectors/reservoirs, and f) introduction of wild and
domestic animals to new geographic areas where the disease is endemic and immunologically
unknown for them (increases zoonotic pool within a geographic region) (Wheelis et al., 2002;
Daszack et al., 2007; Brown, 2010; Cartfn-Rojas, 2012).
Pretreatment of infectious carcasses may be required to improve the mechanical components of
the downstream process equipment and/or to minimize potential biological or physical effects of
the final disposal. Pretreatment enhances the process by increasing the process efficiency and
ultimately productivity (Genesis, 2007). The type of pretreatment will vary according to the type
of feedstock used, the potential level and type of contamination, feedstock size, the carcass
management process to be used, and the desired quality of the end-product (such as dry or
wet). This report has been prepared based on the information collected under a separate report
(U.S. EPA, 2016) that identified eleven infectious carcass pretreatment technologies and
screened them to describe how each technology can be used prior to, and in conjunction with,
the six large-scale carcass disposal options. The six carcass management options considered
were: (i) rendering, (ii) burial, (iii) landfill, (iv) composting, (v) incineration, and (vi) burning. The
eleven pretreatment technologies identified for carcasses were: a) on-site size reduction, b)
digestion, c) bioreduction, d) alkaline hydrolysis, e) sterilization, f) freezing, g) physical
inactivation, h) chemical inactivation, i) additives/sorbents, j) encapsulation, and k) packaging.
The emerging or evolving technologies (such as gasification, plasma technology, irradiation,
thermal depolymerization, dehydration, and extrusion) for treatment of carcasses were not
included within the eleven pretreatment alternatives as these technologies are in research stage
and need additional testing and evaluation.
None of these eleven pretreatments, individually or in combination, should be considered
absolute. The pretreatment scheme should be approached on a case by case basis. Two or
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
more pretreatment/ carcass management options can be selected so as not to overburden a
processing site. Parallel treatment schemes can be considered by using treatment of part of the
feed material by selected technologies while treating remaining parts of the feed material by
other method(s). Based on the critical evaluations of the eleven infectious carcass
pretreatments (U.S. EPA, 2016), three technologies (size reduction, physical inactivation and
chemical inactivation) were shortlisted for additional analysis. These technologies may involve
single or multiple steps. For example, size reduction of carcasses may require prebreaking
followed by grinding. Effort has been made to focus on the key technologies as some of the
sub-processes may be included in the design of a piece of integrated system.
1.2 Analysis of Existing Data and Quality Assurance
An extensive review of the existing literature was an important component of this study. A
literature review was conducted to identify and collect the available peer-reviewed journal
articles, trade fact sheets, reports, guidance documents, and other pertinent information related
to pretreatment for transport of infectious carcasses for management. Various sources of
information on carcass management for large-scale animals, where mortality is due to infectious
agents, were identified. The peer-reviewed articles were downloaded after libraries were
searched across six key databases (Academic OneFile, Academic Search Complete,
MasterFILE Complete, Newspaper Source Plus, OAlster, and WorldCat.org) and other web
science searches. Technical reports released by various Federal Agencies and international
organizations were identified and collected. Additional vendor-supplied data, newsletters, and
fact sheets were obtained. Information included in the report was drawn primarily from peer-
reviewed publications. Peer-reviewed publications contained the most reliable information,
although some portions of the report may contain compilations of data from a variety of sources
and non-peer-reviewed literature (workshop proceedings; graduate degree theses/dissertations;
non-peer-reviewed reports and white papers from industry, associations, and non-governmental
organizations) and unpublished data (online databases, personal communications, unpublished
manuscripts, unpublished government data). Non-peer-reviewed and unpublished sources did
not form the sole basis of any conclusions presented in the report of results. Generally, these
sources were used to support results presented from peer-reviewed work, enhancing
understanding based on peer-reviewed sources, identifying promising ideas for innovative
pretreatment technologies, and provided discussion of challenges. The qualitative ranking has
been performed based on the review of the literature search. Secondary data (Attachment 1)
were used as per the U.S. EPA approved Quality Assurance Project Plan and review of
published or unpublished data for identifying relevant information and assessment in treatment
of infectious carcasses. These secondary data included original research papers published in
peer-reviewed journals and pertinent review articles that summarize original research, obtained
from hard copies and computerized databases. The sources of the data including costs have
been cited. However, no quality assurance (QA) (accuracy, precision, representativeness,
completeness, and comparability) of secondary data has been conducted. The costs obtained
from the literature were cited, indicating the date of publication. The cost information obtained
from a vendor website or via communications was collected during 2014. Unless otherwise
mentioned as equipment rental, the cost numbers are equipment purchase costs. A disclaimer
has been included at the beginning of this report. The data cited in this report were collected
from published literature/fact sheets/web, and no attempt has been made to verify the quality or
veracity of data collected from various sources.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
1.3 Inventory of Large Animals
USDA's National Agricultural Statistics Service (NASS) reported that the number of cattle and
calves in the U.S. as of January 1, 2015, totaled 89.8 million head (USDA, 2015) (see Table 1).
The number of all cows and heifers that had calved was pegged at 39.0 million head. The
number of beef cows totaled 29.7 million head, and the milk cow count totaled 9.3 million head.
Steers (weighing 500 pounds and over) were 15.8 million, bulls (weighing 500 pounds and over)
were 2.1 million, calves (under 500 pounds) were 13.7 million. Cattle and calves on feed for
slaughter in all feedlots were 13.1 million. The combined total of calves (under 500 pounds) and
other heifers and steers (over 500 pounds) outside feedlots was 25.2 million. The National
Renderers Association reported approximately 300 rendering facilities (size reduction is one of
the key steps in rendering) in North America (Hamilton et al., 2007). The United States
processing capacity includes approximately 24.5 billion kilograms (kg) (54 billion pounds) from
100 million hogs, 35 million cattle, and eight billion chickens annually (see Figure 1).
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 1. Cattle Inventory by Class - States and United States: 2015
State
All Cattle and Calves
All Cows that have Calved
(100 head)
(1000 head)
Alabama
1,220
680
Alaska
10
4.6
Arizona
880
370
Arkansas
1,640
870
California
5,150
2,380
Colorado
2,600
890
Connecticut
47
24
Delaware
17
7.5
Florida
1,700
1,040
Georgia
1,040
570
Hawaii
135
72
Idaho
2,300
1,060
Illinois
1,140
470
Indiana
870
380
Iowa
3,900
1,130
Kansas
6,000
1,620
Kentucky
2,060
1,070
Louisiana
790
480
Maine
85
41
Maryland
185
91
Massachusetts
38
18
Michigan
1,140
515
Minnesota
2,330
810
Mississippi
910
480
Missouri
4,000
1,970
Montana
2,500
1,520
Nebraska
6,300
1,840
Nevada
435
245
New Hampshire
30
17
New Jersey
28
14
New Mexico
1,340
730
New York
1,450
730
North Carolina
800
410
North Dakota
1,650
920
Ohio
1,250
550
Oklahoma
4,600
1,940
Oregon
1,300
650
Pennsylvania
1,530
680
Rhode Island
5
2.4
South Carolina
335
185
South Dakota
3,700
1,730
Tennessee
1,730
930
Texas
11,800
4,650
Utah
780
420
Vermont
260
144
Virginia
1,470
730
Washington
1,150
475
West Virginia
370
194
Wisconsin
3,500
1,550
Wyoming
1,300
700
United States
89,800
39,000
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Slaughter
Establishments
• Federal - 556
~ State - 656
Cattle Farms
°-3
4 83
m 84 - 113 ¦401- 950
¦ 114-192 H954 2,404
193 - 400
Million head
85
1990
1995
2000 2005 2010
Year
2015
Figure 1. Cattle Farms arid Federally Inspected Cattle Slaughter Plants (left)
and Cattle Inventory (right) across the U.S. (modified after Gwin and Thiboumery, 2013)
The enormity of US animal agriculture magnifies a number of agricultural biosecurity issues, one
of which is carcass treatment prior to appropriate management. Carcasses can be generally
categorized as small (e.g., poultry and turkey), medium (e.g., sheep and young swine), large
(e.g., mature swine), or very large (e.g., cattle and horses). Handling, treatment and disposal of
larger sized whole carcasses (volume, muscle size and shape, weight) pose operational
challenges on type of treatment, treatment capacity, space, and other limited resources.
Widespread livestock mortalities from either natural occurances or culling (especially large and
very large animal) could pose significant carcass handling, pretreatment and carcass
management challenges. Table 2 provides the average mass, composition, type of waste
generated, energy consumption for typical carcass management, and water consumption during
treatment of various types of animals.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 2. Conversion of Animal Volume and Mass by Species
Type of
Animal*
Average
Mass
(kg)1 5
Composition
(% of Body Mass)2
Waste
Generation
(Industry
Benchmark)
(kg/head)3
Energy
Consumption
(kWh/ton carcass
animal)3
Water
Consumption
(m3/ton carcass
animal)3
Cows
635
Boned tissue**: 40
Bone, fat, head, offal: 39
Hide, tongue, Liver, heart,
kidney, trotters: 12
Blood: 3
Paunch manure,
shrinkage, blood loss: 6
Solid organic
waste: 58
By-products for
rendering: 110
Blood: 10-20
90-1094
Dry rendering: 400-
650
Wet rendering: 570
1.62-9
Rendering: 0.5-1
[1.14 (300 gallons)
per head]4
Pigs/Swine
200
Boned tissue: 64
Bone, fat, head, offal: 20
Tongue, Liver, heart,
kidney, trotters: 10
Blood: 3
Stomach contents,
shrinkage, blood loss: 3
Solid organic
waste: 2.2
By-products for
rendering: 20.8
Blood: 2-4
110-760
1.6-8.3
[0.23 (60 gallons)
per head]
Sheep
80
NA
NA
NA
[0.15 (40 gallons)
per head]4
*One cow, two pigs, three sheep/goats = One animal unit. Auvermann et al. (2004) reported average weights as follows: cattle = 600 pounds, swine =
300 pounds, poultry = 4 pounds.
** Meat generally refers to the skeletal muscle from the carcasses of animals. It is made approximately of (mean value considered for beef meat):
water 70%, protein 21%, fat 8%, and ash (mineral) 1% (Delevoye, 2013)
1: St. John & Associates Projects Inc. (2009); 2: UNEP (2008); 3: International Finance Corporation (2007); 4: Gleick et al. (2003)
5: The average masses (kg) of other animals reported were: Heifers = 455, Bulls >1 year old = 727, Steers >1 year old = 635, Calves <1 year old =
210, Horses = 523, Goats = 80, Bison = 455, Llamas and Alpacas = 75, Hens and Chickens = 1.65, Turkeys = 5, and other Poultry = 2.5.
NA: not available.
1.4 Selected Pretreatment: Size Reduction, Physical and Chemical Inactivation
Based on identification and evaluation of eleven pretreatment alternatives, three pretreatments
(size reduction, physical inactivation and chemical inactivation) were selected based on the
qualitative ranking (see Table 3). None of these pretreatments, individually or in combination,
should be considered absolute. The pretreatment scheme should be approached on a case by
case basis. Two or more pretreatment/carcass management options can be selected so as not
to overburden a processing site. Parallel treatment schemes can be considered by using
treatment of part of the feed material by selected methods while treating remaining parts of the
feed material by other method(s). This section provides general introduction to these shortlisted
technologies and auxiliary activities (such as on-site or off-site treatment/disposal, transport of
carcasses). The subsequent section (Section 3) includes detailed discussions of three
pretreatment technologies (size reduction, physical inactivation and chemical inactivation) on
effectiveness, impact on environment, implementability, control measures, cost, regulatory
issues, personnel safety, and community acceptance as outlined in the performance work
statement. Several of the subsections have overlapping information on pretreatment
technologies. However, they have been described separately under each pretreatment
technology following the guidance for conducting remedial investigations and feasibility studies
under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
(U.S. EPA, 1988).
8
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 3. Carcass Pretreatment Options Matrix
Carcass
Manage-
ment
Option
On-site Size
Reduction
Digestion
Bioreduction
Alkaline
Hydrolysis
Sterilization
Freezing
Physical
Inactivation
Chemical
Inactivation
Additives/
Sorbents
Encapsulation
Packaging
Rendering
++
++
++
++
Incineration
+
+
++
+
++
Composting
+++
Burial
+
Burning
++
+
++
Landfill
+
Notes: Several of the pretreatments may have overlapping processes. Some of the activities can be conducted at centralized or
mobile locations. +++, ++ and + denote qualitative importance of the criteria (+++ > ++ > +), and - indicate not applicable.
Color Key
Subject to acceptability of
Ideal characteristics of feedstock Not Suitable
by the processing facility/plant
Several pretreatments (such as homogenization and separation) are coupled with size
reduction, physical and chemical inactivation that claim to enhance performance (Genesis,
2007). These pretreatments often reduce treatment time and/or improve process efficiency by
increasing the destruction of volatile solids.
1.4.1 Homogenization
A homogenization process can be used prior to and/or during the pretreatment processes to
ensure uniform composition and stable structure of the material, potentially accelerating the rate
and extent of degradation of volatile solids. Selection of appropriate pretreatment technology
with homogenization device can help the efficiency of detection, ease of handling, costs, and
high-throughput capabilities (Rohde et al., 2015).
1.4.2 Separation
Separation of infectious feedstock, if safe to be handled, can be performed to remove materials
that do not require downstream processing (such as removal of grit - sand and gravel, rocks,
and other inorganics). Separation of nonhazardous and nonbiodegradable material that can
ensure a uniform organic feedstock is helpful for the downstream process. Manual sorting at
the source to remove undesirable items prevents or lessens the chance of additional
contamination. Mechanical sorters (screens, rotating trammels, or magnetic separators) may be
considered to handle large volumes of load where the source separation is difficult to achieve,
and manual sorting is inadequate. However, smaller pieces are often not removed and/or are
9
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
mixed into the organic mass by the mechanical process. Source separation of specified risk
material (SRM) (i.e., tissues that contain the agent that may transmit bovine spongiform
encephalopathy (BSE), transmissible spongiform encephalopathy (TSE), or scrapie disease) is
required by the Food and Agriculture Organisation (FAO) when treating animal by-products
(Bohm, 2002; Genesis, 2007).
1.4.3 Size Reduction
Mechanical processes involving size reductions and associated unit operations (such as
shredding, grinding, mixing, agitation, liquid-solid separation, conveying, and compaction)
supplement other carcass pretreatment methods. In the case of downstream physical- or
chemical-based processes, mechanical devices such as shredders and mixers can also
improve the rate of heat transfer or expose more surfaces to chemical inactivation agents.
Mechanical processes can add significantly to the level of maintenance required. Size reduction
may be required prior to various processes (such as rendering, incineration, composting, burial,
burning, and landfill) involving the treatment of animal carcasses. Both North America and the
European Union (EU) regulations specify a particle size > 0.236 inch (Genesis, 2007). To
ensure proper sterilization/inactivation of a pathogen and to expedite the processing of carcass,
feedstock must be reduced to a uniform small particle size. Size reduction of carcasses to an
average particle size of less than 2 inches also allows for better heat distribution and gives
bacteria access to more surface area and improves the efficiency of the degradation of biomass
(Mukhtar et al., 2008). Auvermann et al. (2004) indicated that manufacturing companies design
various forms of milling with a variety of particle size of the feed material to meet the time and
temperature requirements. The particle size of processed material entering various processing
and dewatering systems is as follows: Stork-Duke =1-2 inches, Stord Bartz = 0.8-2 inches,
Anderson Carver-Greenfield Finely = 0.4 inch, and Protec and Stord Bartz Dewatering System =
0.4 inch. Gale (2002) reported that to achieve proper heat transfer in a sterilization process,
animal biomass particle sizes must be no larger than 2 inches. DeWitt et al. (2009) indicated
their preferred particle size range of carcasses is between 1/8 inch and 2 inches as mixtures of
extremely small particles for the composting carcass management option have low porosity.
Poor gas transport through the material can impede movement of oxygen (02) (inflow) and
carbon dioxide (C02) and ammonia (NH3) (outflow). Mukhtar et al. (2008) reported
recommended sizes of less than 1 inch for chemical treatment.
Depending on the carcass pretreatment option selected during an event, size reduction
processes can range from grinding and maceration, involving cutting and shredding, to
pulverization and the reduction of feedstock to slurry in such equipment as a hydropulper.
A number of companies provide equipment that is used for pretreatment of municipal solid waste,
food processing waste, slaughterhouse and animal mortalities. The type and size of the
equipment varies considerably, depending on what material is being processed. Small carcasses
(poultry) require very little grinding and less sturdy equipment but entire bovine carcasses will
have to be processed through prebreaker, shredding or cut up prior to grinding or placed into a
vertical sturdily built grinder.
A literature search conducted to identify companies and their cost estimates found significant
variation; sometimes cost estimates were not able to be acquired. Although not specifically
designed for infectious carcass size reduction purposes, the size reduction equipment and
accessories for the slaughterhouse industry can be adapted for the management of infectious
10
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
carcasses. A bulking agent such as straw is required to eliminate ineffective movement and to
achieve homogenization. A list of representative size reduction equipment and equipment
manufacturers is provided in Table 4.
Table 4. Size Reduction System Manufacturers, Type and Capacity
Size Reduction System
Description
Capacity
Shredder - Machines that tear particles apart (versus smash). The word "shear" is often added as an
adjective, i.e., shear shredder. Compression forces are applied to a particle in offset planes to produce a
shearing action. A common shredder is a low-speed, high-torque shear shredder. This machine uses one or
more rotating shafts, each with a set of cutting disks or knives mounted closely together on the shaft(s) that
sits in a chamber at the bottom of a feed hopper. As the shaft rotates, the cutting devices pull the material
down through the small spaces between the cutting disks/knives and the surrounding chamber. Many
shredders use a pair of counter-rotating shafts that draw the material down, forcing the pieces out between
the two shafts. Particles produced by shredders generally have an elongated shape.
Doppstadt Single Shaft
Shredder, Velbert, Germany
Moderate rotor speed (approximately 32 revolutions per
minute, RPM) mechanical drive leads to longer breaks
between the shredding tools and significantly reduces
noise. Hydraulically controlled shredding comb guides
extraneous objects and produce output material in the size
range between 3.94 inch and 19.7 inch.
60-70
tons/hour
(model
3060K)
MOCO Maschinen- und
Apparatebau GmbH & Co. KG
Viernheim, Germany
Low-noise (idling noise level at 1 m distance approximately
68 decibels) shredder with two counter-rotating toothed
shafts with individually exchangeable cutting disks.
Compact design, sturdy welded construction, low energy
demand.
18-30
m3/hour
Vecoplan LLC
High Point, North Carolina
Once shredded, material passes through bar screens or is
pulled back into the cutting chamber and re-cut until it
passes through the screen bars. The interaction between
the rotors and the counter knife, combined with the bar
screens, produces a homogeneous, consistently sized
output. Systems are available with single and multiple rotor
shredders including conveying technologies, air
classification systems, rotary trammels, vibratory feeders,
oscillating, roller and starscreeners, and separators.
11 to 110
tons/hour
(hopper
capacities
6345 feet3
(maximum)
Crusher - Crushers are used to reduce the size, or change the form, so the end product can be more easily
processed. Crushing is the process of transferring a force amplified by mechanical advantage through a
material made of molecules that bond together more strongly and resist deformation more than those in the
material being crushed. Crushing devices hold material between two parallel or tangent solid surfaces and
apply sufficient force to bring the surfaces together to generate enough energy within the material being
crushed that its molecules separate from fracturing or change alignment in relation to deformation.
Berry Extreme Duty Carcass
Crusher
Clermont, Georgia
Model B-CC-EX crusher decreases carcass volume by fifty
per cent
Up to 350
front half
carcasses
per minute
Harden industry Ltd.
Guangzhou, China
Prebreakerfor complete carcasses (model DS81)
Cost: $60,000 - $80,000/unit Freight on Board (FOB)
Guangdong, China
35 tons/hour
Haarslev Industries A/S
S0nders0, Denmark
PB30/60 Animal Crusher can handle whole carcasses and
is installed in rendering industries
15-50
tons/hour
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Size Reduction System
ANCO-EAGLIN Inc.
Greensboro, North Carolina
Description
Designed for bone crushing or whole carcass crushing.
One-pass design that discharges a particle size suitable
for feeding any conveying system and enough for any
batch or continuous rendering process. Duracut crusher
with no infeed equipment or removal equipment $150,000.
10 large cattle/hour. Can handle over 10 tons/hour for
small hogs (under 0.35 ton). Large sows would be one at a
time like the cattle.
5-50
tons/hour
The Dupps Company
Germantown, Ohio
Precrusher: Breaks large pieces without preliminary cut-
up-
25-50
tons/hour
Grinder - Grinders reduce particles in size by repeatedly pounding them into smaller and smaller pieces
through a combination of tensile, shear and compressive forces. Nearly all grinders, including tub and
horizontal feed grinders, rely on a hammermill as the pounding device. A hammermill has club-like
projections (hammers) attached to a rapidly rotating drum (rotor). The high rotational speed (more than
1,000 RPM) gives the hammers enough inertia to shred the material (Goldstein and Diaz, 2005). As the
drum rotates, the hammers spin rapidly and smash against the material trapped inside the hammermill
chamber until the pieces are small enough to pass through the discharge screen or grate. To be effective,
the material being ground has to be somewhat rigid and brittle, although the hammers will eventually
pulverize almost anything. Particles coming out of a grinder look ragged, broken and smashed. The particles
encompass a wide range of shapes and sizes (smaller than the screen opening).
DuraTech Industries
Jamestown, North Dakota
Model 4012 Industrial Tub Grinder capable of large volume
grinding
70-120
tons/hour
(-9450
feet3/hour)
Diamond Z
Caldwell, Idaho
Stationary and mobile grinders (tub and horizontal
grinders)
70-100
tons/hour
KPI-JCI and Astec, Yankton,
South Dakota
Crushing, screening, material handling, washing,
classifying and feeding equipment
290-875
tons/hour
MAVITEC
Heerhugowaard, The
Netherlands
Extra heavy carbon steel construction, replaceable wear
resistant cap and base liners, replaceable hammers,
screens supported by chain cradle construction, and
carbon steel platform.
1 -3
ton/hour
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
1.4.4 Inactivation
The challenge associated with the management of animal carcasses includes protection of
environmental, animal, and public health against potential microbiological threats. An animal
carcass is composed of microbiologically active material that may contain viruses, bacteria,
protozoa, parasites, prions, and toxins. All of the biologically active materials need to be
reduced to safe amounts, eliminated, or contained to minimize their potential hazard.
Inactivation is the process of eliminating pathogenic microorganisms from inanimate objects.
Different inactivation methods have different target ranges, and not all methods can kill all
microorganisms. Inactivation is different from sterilization, which is an absolute condition where
all the living microorganisms including bacterial spores are killed. Physical inactivation includes
application of dry heat (flaming, hot air oven, infrared), moist heat (below 100 °C, at 100 °C,
above 100 °C), ultra-high pressure steam, energy (thermal, plasma arc irradiation, pulsed-field
electricity, ultrasonic energy, UV light). Chemical inactivation is the use of chemical agents
including oxidizers (chlorine, hypochlorite, ozone, and peroxide), organic acids (lactic acid,
acetic acid, and gluconic acid), organics (benzoates, propionates), bacteriocins (nisin, magainin
[antimicrobial peptides]), acidic and basic electrolyzed water. Inactivation can be used in
conjunction with other carcass pretreatment processes such as size reduction.
1.4.5 On-Site or Off-Site Treatment/Disposal
Historically, treatment and disposal of diseased carcasses was done on the infected premises to
avoid spreading the infection by transporting the carcasses to an off-site facility. However, the
onsite treatment technologies and carcass management options have potentially serious
environmental consequences and may be limited by space requirements and access to bulking
agents such as wood chips, straw, peat moss or carbonaceous materials. While on-site
treatment or disposal may still be a preferred option, off-site methods may increasingly be used
in emergencies, particularly for the carcasses of large animals. A decision to move the carcass
management activities off-site will be related to the scale of the event (i.e., the volume of
material), site capacity, potential human health concerns and environmental concerns. For off-
site management, the primary issue will be to identify a suitable site for carcass management
and the transportation of carcasses in a safe, sanitary and timely fashion to avoid spreading the
disease and/or endangering public health.
1.4.6 Activity Prior to Transport of Carcasses
Transport of infected carcasses must be planned and executed with care, utilizing leak-proof
vehicles approved for transporting hazardous material. Refrigerator trucks may be used.
Vehicles should not be overloaded - at least 24 inches freeboard, depending on distance to be
travelled and temperature, should be left clear for expansion of carcasses. Smaller carcasses
should be bagged if feasible and larger carcasses covered with a layer of polymeric sheeting. If
vehicles are not enclosed, they should be lined and an airtight vinyl tarp should be placed over
the top. All vehicles must be cleaned and disinfected before leaving the infected premises and
after unloading. Vehicles should travel on designated routes, preferably with an escort vehicle.
They must travel slowly to avoid splashing of contaminated material and a supply of an
approved disinfectant should be carried to deal with minor spills during transit. Carcasses and
other items awaiting management should be secured to prevent unauthorized access and to
prevent wild animals and birds from removing potentially infectious material. Control of insects
should be considered if there is a risk of passive transmission by insects to nearby susceptible
species. If carcass management is delayed, carcasses should be thoroughly sprayed with an
13
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
approved disinfectant. Federal, State, and local transportation, public health and waste
management officials should be consulted ahead of time to ensure all transportation
requirements are considered prior to off-site transport.
Use of plastic bags and similar material is recognized to be necessary for operator protection.
However, their use should be minimized by use of mechanized and automatic feed devices due
to potential impacts on the operation of the equipment. Carcasses and by-products may need
to be classified according to source (for example, specified risk material). United Nations
Environment Programme (UNEP) (2006) recommends that the methods to be considered
include:
• Use of mechanized loaders to avoid contact with carcasses;
• Use of macerating and grinding techniques to allow automatic continuous loading and
operation; and
• Minimizing contamination from packaging, including use of non-halogenated plastics.
14
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.0 Evaluation of Individual Alternatives
2.1 On-site Size Reduction
Size reduction of carcasses typically involves physically breaking material into smaller particles
or pieces. The three most common methods for size reduction are grinding, shredding and
crushing. Carcass materials can undergo size reduction through different mechanisms: impact
(sharp, instantaneous collision of one moving object against another), compression (occurs
between two surfaces, with work being done by one or both surfaces), attrition (reduction of
material by scrubbing it between two hard surfaces) or a combination of these crushing
methods.
Size reduction equipment can be broadly categorized as crushers, grinders, and shredders,
where grinders produce finer particles than crushers. Size reduction in impact crushers occurs
through particle concussion by a single rigid force. The swing hammer crusher is an example of
an impact crusher. Table 5 provides the advantages and disadvantages of shredder, crusher,
and grinder.
Table 5. Advantages and Disadvantages of Shredder, Crusher, and Grinder
Shredder
Crusher
Grinder
Advantages
Disadvantages
Advantages
Disadvantages
Advantages
Disadvantage
s
• Preliminary
• Cutting
• Energy
• Limited size
• Large range of
• Energy
step for large
equipment is
efficient.
reduction.
equipment
consuming.
feed to shred
relatively
• Does not
capacities are
• Rings, pins,
down to
expensive due
over-
available.
or rollers
random,
to abrasion.
reduce
• Creates
wear easily.
smaller
materials.
homogeneous
• Output limited
components.
• Variable
blend.
to less than
• Uses low
capacity.
% inch to 1/2
speed and
inch.
high torque.
• Output ranges
between 1
inch and 2
inch and
larger.
Size reduction equipment is manufactured in a wide range of capacities and feedstock size
ranges. Equipment for size reduction may also be integrated with densification or drying
equipment because smaller particle sizes can be compressed and dried more efficiently
(Tallaksen, 2011). When evaluating equipment, there are several considerations and options
that make systems suitable for specific uses. Among these considerations are noise level, dust
generation, energy consumption, tolerance to moisture, and the final feedstock size. The most
commonly used size reduction equipment is a hammermill grinder, which has high speed rotors
with metal hammers that essentially beat biomass apart until it fits through the openings of a
metal screen. The size of the openings in the screen determines the final size of the processed
biomass. While these hammermill systems have a high throughput and are very simple to
operate, they are also very noisy and can create a significant release of biomass via splash.
Maintaining rotational speed as the hammers strike the carcass requires that rotors be driven by
15
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
high amperage electric motors or large diesel engines. Hammermill units are found in most
biomass processing systems due to their reliability and flexibility in working with multiple types
of feedstocks. Changing processed particle sizes is often as simple as switching screens. High
moisture containing carcasses can bind and jam the unit and will definitely reduce throughput.
Depending on the hammermill, large chunks of dense biomass may also be difficult for the unit
to break apart efficiently. However, both moisture and density issues can be overcome with
equipment modifications and a larger motor.
A shredder can process moist, dense, or stringy carcasses effectively. Although often grouped
with grinders, shredders tend to be low speed, high torque units that have large teeth to pull
apart material. These units have large motors that are connected hydraulically or with reduction
gears to the shredding rotor to generate the force needed for processing resistant material.
Shredders are much quieter than hammermill grinders because of the lower rotational speed
and the lack of hammer strikes on the material. Low speed operation also reduces aerosols.
The key disadvantages of shredders are the relatively low throughput and limited flexibility in
altering the final particle size. Shredding is normally used as the first processing step.
Shredders are well suited for the primary breakdown of large dense feedstocks but may need to
be paired with a secondary processing system that reduces material to a final uniform size.
Crushers can be used with dry whole carcasses or bone materials that will shatter under
pressure. The advantage of using a crusher is that it is a lower energy process than either
grinding or shredding. Most biomass is too fibrous or wet to shatter and will densify as the large
rollers put pressure on the biomass.
The selection of the type of equipment available for the size reduction or comminution of
carcass materials is dependent on the raw material and the type of product of the processing
(such as grindability, sticky, hard/soft, graded, granular, fine, abraded, rounded, sharp, etc.)
required.
The laws of size reduction in general use include those of Rettinger, Kick, and Bond (Galanty,
2007). Rettinger's energy, W, required for grinding can be determined by W = KR (R - 1 )/U
where W is total energy required for size reduction; KR is Rettinger's constant; fc is crushing
strength; U, L2 are the initial and final dimensions of the particles; and R is the size reduction
ratio, U/l-2. Kick's law is generally favored for coarse crushing:
W = Kk fc In R
where Kk is Kick's constant. The energy obtained from this equation is a function only of the
size reduction ratio and does not depend on the initial or final sizes.
Bond's law is applicable to both coarse and fine grinding:
(yjO.5 _ i \
[05 J
where Wi is the Bond work index.
The size and distribution of the carcass material significantly influences the particle size
obtained from size reduction equipment. Smaller sizes can be controlled by clearances within
the equipment and speed and the retention time. Forces can be applied as compression,
tension, shear, impact, and attrition. In size reduction equipment, there is usually more than
16
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
one of these forces acting on the material, although one may be predominant. Tension is the
cause of fracture in brittle materials (bone, hoof, horn), yet no practical size reduction equipment
applies a primarily tensile force. Brittle materials when subjected to compression in a double roll
crusher or in a jaw crusher apparently fracture under tension. The mechanical properties of the
cattle horn sheath reported by Li et al. (2010) are distinctly dependent on the hydration
condition. The sheath is brittle at 0% water content but ductile at 8% and 19% water content
based on the stress-strain curves (Li et al., 2010). Compression-type equipment is easily
applied to brittle substances but must be more carefully applied to ductile and soft (tissue)
materials to avoid flattening or compaction. Shear forces can be introduced by compression-
type equipment (such as disk mills) by causing one disk to revolve at a different speed from the
other.
While size reduction is governed by basic laws of physics, no single law or rule can take the
place of experience and testing in the selection and sizing of suitable size reduction equipment
for a given application. A number of factors go into the proper selection of a piece of size
reduction equipment for a given application, including the following.
• Will the size reduction equipment handle the maximum required capacity to be
processed without undue strain or overload?
• Wll the machine handle the maximum size (whole carcass) of the infeed material?
• Wll the unit's operating mechanism handle the properties of the material (such as tough,
sticky, soft)?
• Is the design and construction suitable for the special application requirements such as
resistance to corrosion, maintenance of purity or sanitary requirements?
• Wll the size reduction equipment produce the output particle size required?
• Wll the equipment produce aerosol or splash material?
• Wll the equipment operate with minimal noise or vibration?
• How will the material be fed? Conveyed or dropped by gravity?
• Does the size reduction equipment match the connection configuration (dimensions:
round or square)?
• Is the equipment suitable for the operating conditions and operating temperature?
• Does the unit meet the requirement for ease of maintenance and interior access?
• Does the size reduction equipment have seals adequate for the application?
• Is qualified field service and customer support available from the supplier?
• Is the machine built with high quality materials and workmanship?
• Is the size reduction equipment configuration suitable to fit in the available space?
Carcass materials differ in properties as they can be weak, strong, and soft or hard (USDA,
2012), as defined by Young's modulus (Chen et al., 1996), and any combination of these
conditions can be met in the size reduction process. Figure 2 provides stress-strain relationship
for processing material properties. The first straight line part of the curve follows Hooke's law-
i.e., stress is proportional to strain, and the ratio of stress to strain (modulus of elasticity)
measures stiffness or softness in pounds per square inch (or dynes per square centimeter).
Stress at the knee of the curve is the first yield point that measures resistance to permanent
deformation. The total area under the stress strain curve represents the energy required and is
also a measure of toughness or impact strength (Figure 2). Three types of force are used to
reduce the size of carcasses: a) compression forces, b) impact forces, and c) shearing (or
17
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
attrition) forces. In most size reduction equipment, all three forces are present, but often one is
more important than the others. In Figure 2, E = elastic limit; Y = yield point; B = breaking point;
O-E = elastic region; E-Y = inelastic deformation; Y-B = region of ductility; (1) = hard, strong,
brittle material; (2) = hard, strong, ductile material; (3) = soft, weak, ductile material and (4) =
soft, weak brittle material. When stress (force) is applied to a material, the resulting internal
strains are first absorbed to cause deformation of the tissues. If the strain does not exceed a
certain critical level named the elastic stress limit (E), the tissues return to their original shape
when the stress is removed, and the stored energy is released as heat (elastic region, O-E in
Figure 2). However, when the strain within a localized area exceeds the elastic stress limit, the
material is permanently deformed. If the stress is continued, the strain reaches a yield point (Y).
The breaking stress is exceeded at the breaking point (B), and the material fractures along a
line of weakness. Part of the stored energy is then released as sound and heat. As little as 1%
of applied energy may actually be used for size reduction.
Table 6 provides the selected size reduction equipment including shredder, prebreaker, chipper,
chunker, hammer hog, hammermill, knife mills, and disk mills. Hammermills and tub grinders
are common size reduction equipment to process large carcasses, and brief discussions are
included in this section.
18
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Soft, weak
u>
Hard, brittle
I
Strain
Hard, strong
Soft, tough
Strong
Weak
Strain
Figure 2. Stress and Strain Relationship:
The moduius of elasticity is low for soft materials and high for hard materials
(Modified after Fellows, 2000),
19
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 6. Types of Size Reduction Equipment
Equipment
Shredder
Prebreaker
Chipper
Chunker
Hammer Hog
Hammermill
Knife mills
Disk mills
Types
• Horizontal
Pre-break large
Disk type
• Spiral head
» Swing
• Swing
Material is fed to
Size reduction
• On-site
shaft with
pieces without
chipper
• Involuted
hammer
hammer
the cutting
takes place by
• Mobile
top- or side-
preliminary cut-
• Horizontal
• Double
» Fixed
• Fixed
chamber via a
cutting and
/Portable
feed chute
up. Hardened
feed
involuted
hammer
hammer
chute. Size
shearing
• Controlled
machined teeth
• Gravity feed
» Punch and
• Tub grinder
reduction takes
action
feed type
force material
die
• Rotary knife
place between
between
with
through the
Drum type
» Mass rotor
hammer
rotor and
toothed
compression
prebreaker's
chipper
» Knife hogs
housing knives.
segments or
feed device
rugged anvils
• Horizontal
The size of the
alternatively
for positive
with a low-speed
feed
end product is
with high
feed and
shearing action
• Gravity feed
determined by a
pressure
uniform
instead of an
screen installed
refining disks.
power load
impact or tearing
in the lower part
• Reversible
action
ofthe housing
centerfeed
• Flail mill
Reduction
Swinging
High-strength
Replacement
Rotating
Swinging/
Swinging/fixed/
Replacement
Cutting disk
Device1
plates/knives
alloy teeth
knives
impact
fixed/
semi-sharp
knives
with blade
or rotor
surface
semi-sharp
hammers
hammer
cutter
hammers
Speed1
Moderate
Low
High
Moderate
Moderate
Moderate
Moderate
Low
Geometry
Coarse/multi
Semi-coarse
Clean
Coarse/multi-
Coarse/
Coarse/
Semi-coarse
Semi-coarse
of Output
-surface
edge/two-
surface
multisurface
multisurface
sided
1: Hoqueetal. (2007)
20
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Hammermill
Hammermills are commonly used impact crushers in which the load, a combination of tensile,
compressive, or shear forces, is applied to the material by striking the particles in suspension or
by hurling them at high speed against stationary surfaces. This action differs from a typical
crushing unit such as a rock crusher, which takes a coarse feed and applies pressure gradually
to the material which takes the load as simple beams or short columns. The greater part of size
reduction by the hammermill is accomplished by brute force. There are horizontal and vertical
shaft machines of either swing or rigid hammer type. The principal parts of the horizontal swing
hammer unit are the rotor, hammers, grates, frame, and flywheel. The hammer configurations
vary from simple rectangular blocks (typical dimensions of 12-inch x 4-inch x 1-inch) to the
more elaborate type of chopper, which may have a protruding wearing surface with sharpened
edges. Material to be size-reduced enters the equipment through an infeed chute and interacts
with the hammers and each other until at least one dimension of the object has reached a size
small enough to fall through the grates in the bottom of the unit. Due to rotating hammers,
certain portions of the object may be thrown out or ejected because of the impact with the
swinging hammers. These airborne objects, which may leave through the input opening, are
potentially hazardous to the operators of the equipment. A curtain is often hung over the input
opening to deflect the objects that are ejected. In the vertical shaft unit, the rotor is placed in a
vertical position, with the input material moving parallel to the shaft axis, assisted by gravity.
This unit is relatively slow-turning and does not tend to reject objects in the manner of horizontal
shaft hammermill. Rynk (2003) demonstrated that chopping large carcasses in a vertical
grinder-mixer produces a homogeneous mixture for downstream processing (rendering and
composting) and eventual disposal.
Tub Grinder
A tub grinder can process animal carcasses into smaller pieces by means of a hammermill
located at the bottom of the tub. The feed material is placed in the top of the tub that rotates to
feed the material into the hammermill. A screen around the hammermill limits oversize material
from passing through to the conveyor system that either can feed into a transport container or
can be piled onto an intermediate storage container to be loaded later. Models of tub grinders
are available on a trailer or self-propelled track carriers.
The method of feeding in most of the tub grinders imposes a heavy shock load on the power
train and results in wide power fluctuations. A tractor with a higher power take-off output is
needed to prevent tractor stalling due to the power fluctuations. Smaller tractors could be used
at reduced grinding rates by adjusting the tub governor. The maximum grinding rate for a tub
grinder depends on the type of biomass being ground, its moisture content, temperature, the
screen size used, and the available tractor power. Screen size is the most important operating
factor directly affecting grinding rate, power consumption and specific capacity. Reducing
screen size by a factor of two generally doubles power consumption and halves the grinding
rate and specific capacity. The advantage of the tub grinder is that it is generally easier to
perform maintenance. Tub grinders require high power input to produce modest throughput
(Hoque et al., 2007). The tub grinders may not process whole carcasses without bucking. They
have a higher feed height than other grinders, which may limit visibility or feasibility of certain
loading methods (such as skid steer with brush attachment) (Smith, 2013).
21
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Trade-offs between coarse and fine size distributions should be considered in terms of
producing a feed material with uniform characteristics and yet not creating an energy intensive
pretreatment process if fine grinding is required as a secondary size reduction stage.
2.1.1 Effectiveness
Size reductions of the carcass provide the following advantages: 1) creating more surfaces
(more sites for rapid sterilization, biodegradation for composting, or oxidation in a combustion
process); 2) homogenizing the feed material to provide uniform properties for the downstream
processing; 3) multi-stage size reduction units can provide flexibility in the carcass handling
operation; 4) preprocessing such as chopping and/or mixing of carcasses helps isolate the
fibrous or tissue material from unwanted material; and 5) meeting specifications on size and
shape by the downstream processing for easier handling with improved blending efficiency
(Wilkinson, 2011).
2.1.2 Impact on Environment
There are environmental issues associated with carcass processing and management options.
The decision-makers in the choice of the proper treatment and disposal option should factor the
environmental concerns into the decision process so that potential negative consequences can
be avoided. The key ten environmental resources issues are: i) solid waste, ii) groundwater, iii)
surface water, iv) air quality, v) climate, vi) public health, vii) wildlife, viii) cultural resources, ix)
utilities, and x) vegetation (Ellis, 2001). If the death of an animal was due to an infectious
organism, then the method that most efficiently prevents further disease spread is usually the
preferred choice. Protecting livestock from a disease needs to be weighed against protecting
humans from environmental hazards. When a natural disaster is the cause of death, the
pretreatment technologies and carcass management options chosen should be the most
environmentally acceptable. Catastrophic situations that created large numbers of carcasses in
the past indicated that the most expeditious method may be utilized in an effort to solve the
problem. Biosecurity, environmental, and logistical issues affecting carcass pretreatment and
disposal should be reviewed to select the appropriate method of carcass management for
various situations. Some disease agents are readily transmitted to other susceptible animals by
transportation off-site, so biosecurity measures must be strictly enforced against an infectious
agent.
When selecting a size reduction processing site, it is critical to consider the environmental
impacts. The location of the site should minimize the impact of odor and other air quality issues
on any neighboring residences and prevent the movement of nutrient-containing water into
surface water and groundwater. Other considerations include the direction of prevailing winds,
the distance to property lines, proximity to recreational or public sites, aesthetics and the slope
of the site. Michigan has specific criteria that carcass processing sites must meet (BODA,
2015):
• A well-drained area with a minimum setback of 200 feet from water (including lakes,
streams, wetlands, sinkholes, seasonal seeps or other landscape features that
indicate the area is hydrologically sensitive).
• A minimum of 2 feet above the seasonal high water table.
• A minimum of 200 feet from any well.
• A minimum of 200 feet from the nearest neighboring residence.
22
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
These factors should all be taken into consideration in determining if a carcass pretreatment
facility is appropriate and, more importantly, the type of carcass management that should be
considered. There does not appear to be any consensus among governing entities as to the
exact distance that sites should be located from specific areas of concern such as wells or
homes. There is obvious disparity among states in the recommended offset distances (and
depths) for burial sites from the multitude of limiting factors in the selection process (Table 7)
Table 7. Recommended Distances by Selected Agencies
Agency
Minimum Distance
from Streams
(feet)
Minimum Distance
from Water Wells
(feet)
Minimum Distance
from Dwellings (feet)
USDA READEO'
150
150
100
Arkansas Department of
Agriculture
600
600
none
Wisconsin Department of
Agriculture
150
300
100
North Carolina Department
of Agriculture
300
300
none
California Department of
Food and Agriculture
100
1000
100
1: Regional Emergency Animal Disease Eradication Organization (READEO).
Other states have minimum offset distances from the above considerations as statute or
guidelines to follow. These issues need to be identified in advance by state and local
emergency response officials, and mechanisms to waive or modify pre-existing regulations as
needed in emergencies should be negotiated in advance. Dr. Mark Sobsey (University of North
Carolina, Chapel Hill) raised questions regarding the adequacy of a 75-foot buffer between
spray fields and residential property as potential human exposure from the spray may be difficult
to control. Studies of the spraying processes have shown that there is some drift away from the
spray area. Sobsey recommended a barrier (such as tall vegetation) to disrupt the dispersal of
airborne microbes in addition to a sufficient setback distance (Craven County, 1997).
2.1.2.1 Odor
Size reduction may increase the risk of odor problems, particularly if the equipment is not part of
an enclosed and exhausted continuous system (European Commission, 2005). Decomposition
commences as soon as the carcass has gone through the size reduction process. Undue
delays before rendering (or other carcass management option) in conjunction with inadequate
temperature control have a direct effect on the state of decomposition and on the consequent
severity of any odors. The biological and/or thermal decomposition of carcass materials leads
to the formation of odor-intensive substances such as ammonia and amines, sulfur compounds
such as hydrogen sulfide, mercaptans, and other sulfides; saturated and unsaturated low-boiling
fatty acids; aldehydes; ketones and other organic compounds. Measurements have shown that
the average odor concentration can be 80-800 kilo odor units (kOU)/kg raw material (Ireland
EPA, 2008). The concentration of odor at the detection limit has been defined to be 1.0 OU/m3,
so that odor emissions can be expressed in odor units per second (OU/s) or odor units per
second per animal unit (AU), where 1 AU = 500 kg animal weight (OU/s/AU) (Bottcher, 2001).
23
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
The malodorous emissions can also arise from gaseous emissions from downstream
processing operations (such as rendering). Odor emissions also arise from discharges from
cookers, presses and/or centrifuges receiving hot rendered material for separation and hot
separated material prior to storage. Other sources include the displacement of malodorous air
from the tallow storage tanks; the cleaning of process equipment; fugitive emissions from
process buildings and the operation of an odor abatement plant beyond its design
specifications. Malodorous emissions also arise from liquid effluents, including the accumulated
liquid at the base of the raw material transport containment and on-site storage hoppers;
material spillages and floor washings; cooler condensate; the by-products of abatement
techniques and treatment/effluent holding tanks. The storage and handling of animal meal and
tallow can also cause odor problems. The non-condensable gases and the condensate liquor
have a particularly strong and offensive odor. If the odor is not destroyed at the source, odor
can cause problems from within the installation and at the wastewater treatment plant. The
National Renderers Association reported that odorous gases generated at various points in the
process can be collected by a ductwork system and can be transported along with the non-
condensable gases from the condenser to an odor control system for neutralization of odorous
components (Hamilton et al., 2007).
The odor from a carcass size reduction processing facility can be detected if odorous gases are
generated, released to the atmosphere, and transported to the receptor. Interference with one
of these steps diminishes odor. Ways to diminish odors include solid separation and
biofiltration. Biofilters reduce odor by directing airflow through filters and can be expensive due
to the energy costs to operate the fans at higher operating pressure, sprinkling costs to keep the
filter moist, and cost to replace the media after five years (VA DEQ, 2001; Nicolai and Lefers,
2006). The installation and operation and maintenance costs are highly variable. The
estimated cost of installation of a biofilter is $150 to $200 per 1000 cubic feet per minute (cfm)
fan capacity. Biomass filters may provide an economical solution as they hang outside the
buildings in front of fans, allowing dust to settle out of the air and thus reduce odor, since dust
transports odor and microbes (Craven County, 1997; Bio-Oxygen, 2012).
2.1.2.2 Infrastructure and Accessibility
Drainage around the size reduction facility is particularly important. Water should not pond
around the processing area. Access to the equipment with loading, storage and transportation
vehicles should be provided. A solid base (such as concrete or asphalt) and anti-vibration
cushioning can provide a solid and impervious foundation for the operation and maintenance of
the equipment. Constructing a temporary physical barrier (perimeter fence) around the facility
may help prevent scavenging wild animals from rummaging in the vicinity. Constructing a
temporary physical barrier can be accomplished using materials such as chain-link or equally
restrictive fencing with a gate or gates. Proper care should be taken by cleaning and/or
covering the carcass residues, if any. Bulking agent and a biofilter covering of exposed carcass
material can provide preventive measures. A biofilter cap is a layer of fresh bulking agent
(carbon-rich materials such as chopped straw, dried grass, chopped dried hay, and sawdust or
shavings) placed over the processed carcass to reduce odors and discourage pests. Nitrogen-
rich materials such as animal manure solids, partially decomposed materials, green grass
clippings, freshly cut forages, green leaves and litter cake are less effective in controlling odors,
insects and vermin and are not recommended (Rozeboom et al., 2013).
24
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.1.2.3 Wastewater Treatment
Size reduction of carcass material normally performed by closed system without generating any
wastewater (Eaglin, 2015). Wastewater from cleaning and sanitizing equipment and building
surfaces, and spillage should be contained and transported to offsite treatment facility. If not
contained, the wastewater containing high loading of solids, floatable matter, and organic
substances requires an onsite wastewater treatment facility. The concentrations of biological
oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS),
nitrogen, phosphorous, coliforms, and pathogens are highly variable depending on processes
and effectiveness of solids separation. Based on an estimated daily water use of 4.54 m3
(1,200 gallons) and the values for BOD and TSS as 150 mg/L and 58 mg/L, respectively, the
estimated hook-up charge by a new small plant in Washington was $51,950 (Hardesty and
Harper, 2013). A BOD level of 2,500 mg/L, as reported Hardesty and Harper (2013), increased
the hook-up charge to $275,000, while the other values remain unchanged. A 200 gallons per
day modular or fixed water treatment system cost reported to vary between $137,000 and
$147,000 (Hardesty and Harper, 2013).
The wastewater requirements of the state water quality control board and regulations that the
wastewater treatment facility will need to comply with must be considered. Certain states (such
as California) have stringent water quality requirements, and wastewater treatment designs
require careful planning. The North Coast Regional Water Quality Control Board (NCRWQCB)
regulates the discharge of waste to surface waters as well as to storm drains, ground surfaces,
and to ground waters in the California North Coast region. The NCRWQCB is responsible for
enforcement of the National Pollutant Discharge Elimination System (NPDES), which includes
regulating the discharge of waste to ground surfaces or groundwater and a permitting,
surveillance, and enforcement program.
2.1.3 Implementability
State and local governments may have regulations for specific types of operations, which can
include infectious animal carcass processing facilities. These typically relate to worker and
public health and safety regarding aerosol emissions, noise levels, and hazards of projectiles
(objects that can be thrown from grinders, shredders or other size reduction systems). The
following section discusses the preventive and mitigation measures and regulatory requirements
(both for worker health and safety and public nuisances).
2.1.3.1 Aerosol Control
Air can act as a potential vector of contaminants of carcasses and equipment (Pearce et al.
2006). Pathogens can potentially become airborne owing to the sanitation maintenance and
carcass processing, especially within solid particles suspended into the air as single organisms
or in droplets in the form of aerosols (Spurlock and Zottola, 1991). Pathogens could potentially
be transmitted by air and colonize various surfaces. Infectious airborne particles can be
produced from atomized liquids in which the pathogenic microorganisms remain as droplet
nuclei. Although to initiate infection, much depends on the density, size and the degree of
aggregation of the particles to be able to bypass the protective mechanisms of the nose and
reach the alveoli of the workers. Dobeic et al. (2011) recognized that there is still insufficient
information available about the environmental conditions, routes, and sources, and on how
pathogens can become airborne. The bacterial numbers in the aerosol may reflect specific
facility practices and temporal influences. The working procedures result in the formation of
25
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
aerosols containing different particle sizes and contamination with different numbers of
microorganisms. The predominant bacteria in cattle are reported to be S. epidennidis, E.r
agglomerans, C. freundii, E. coli, Salmonella sp. and E. aerogenes with smaller proportions of
S. aureus, H. alvei, C. diversus, P. mirabilis and other bacteria (Vazquez-Moreno et al., 1990).
Vazquez-Moreno et al. (1990) reported that the predominant bacteria in chicken were E. coli, S.
epidermidis and H. alvei and smaller proportions of E. agglomerans, P. mirabilis, Salmonella
sp., C. freundii, C. diversus, M. morganii, S. liquefaciens, P. vulgaris, S. arizona, Pseudomonae
and S. aureus. Appearances of airborne pathogens are feasible at locations where the
potentially contaminated aerosol was spread into the air, with the air contamination by
microorganisms increasing and microclimatic properties being suitable. Wheatley et al. (2014)
reported that contamination can be introduced at various steps in the size reduction processes.
These authors reported relatively high numbers of total viable counts (TVC) and
Enterobacteriaceae (EB) at several stages of a size reduction process and highlighted the
usefulness of monitoring more than one location within the process for each facility so that high
risk stages can be identified, increased controls implemented and ongoing monitoring carried
out to assess the effectiveness of additional interventions.
Measurement of aerosolized microorganisms relies upon the collection of a sample into or onto
solid, liquid or agar media with subsequent microscopic, microbiological, biochemical,
immunochemical or molecular biological analysis. Two distinctly different approaches are being
distinguished for the evaluation of microbial exposure: culture-based methods and non-culture
methods. Instead of counting culturable or non-culturable microbial propagules, constituents or
metabolites of microorganisms can be measured as an estimate of microbial concentration.
Toxic (e.g., mycotoxin) or pro-inflammatory (e.g., endotoxin) components can be measured, but
non-toxic molecules may also serve as markers of either large groups of microorganisms or of
specific microbial genera or species. The use of advanced methods such as polymerase chain
reaction (PCR)-based technologies and immunoassays can detect and speciate regardless of
whether the organisms are culturable. Table 8 gives an overview of assessment methods for
constituents of microorganisms (Douwes et al., 2003).
Table 8. Assessment Methods for Microorganisms in Bioaerosol Samples
Microorganisms
Aetiological Agent
Marker
Analytical Method
Gram-negative bacteria
Endotoxin (LPS)
LAL
3-Hydroxy fatty acids
GC/MS
Gram-positive and Gram-
negative bacteria
Peptidoglycans
Muramic acid
GC/MS
Fungi
p(1—>3)-Glucans
LAL, ELISA
Ergosterol
GC/MS
EPS
ELISA
mVOCs
GC/MS
Fungi/bacteria
Allergens
ELISA
Mycotoxin s
TLC, HPLC, GC/MS,
RIA, ELISA
DNA
PCR
LPS: lipopolysaccharide; LAL: Limulus amebocyte lysate; GC/MS: gas chromatography/mass spectrometry; ELISA: enzyme-linked
immunosorbent assay; TLC: thin layer chromatography; RIA: radioimmunoassay; PCR: polymerase chain reaction; mVOCs:
microbial volatile organic compounds; EPS: extracellular polysaccharides; HPLC: high performance liquid chromatography; RIA:
radioimmunoassay.
26
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Most manufacturers offer, either as a standard feature or an option, aerosol control systems on
their grinders/shredders, screens and turners. In other cases, the equipment design or its mode
of operation can keep aerosols under control. For example, Bandit Industries' horizontal grinder
turns at a slower rotation and moves downward toward the material so that the aerosol is
directed into the mill, not upward (US Compost Council, 2001). Collection augers retain dirt and
debris until it is forced out of the discharge. The grinder also has a dust suppression system
that sprays water before, during and after the grinding process. The Vecoplan (Archdale, North
Carolina) grinder also has a low speed cutting rotor (approximately 80 to 120 RPM), and a
pneumatic hood is engineered as part of the design for capturing aerosols and conveying chips
from the discharge. The cutting rotors on the Komptech (Frohnleiten, Austria) high torque, low
speed shredder sold in the U.S. by Norton Environmental Equipment (Independence, Ohio) run
at a low RPM (30 to 36), which minimizes aerosolization from the process. Amada Machine
Tools America, Inc. (Schaumburg, Illinois) grinders/shredders have enclosed infeed chutes and
its disc and trammel screens come with optional top covers. Rotochopper grinders
(Rotochopper, Inc., St. Martin, Minnesota) are equipped with either a grinder chamber or an
aerosol/dust control chamber. The Peterson Pacific Corp. (Eugene, Oregon) grinders have
discharge conveyor covers. Paying attention to wind direction, feed material condition before
grinding, and frequent cleanup of both the machine and the surrounding area are important.
Process controls should include turning upwind, stockpiling material as wind barriers, containing
the output conveyors on screens and positioning equipment (such as building a wind barrier to
the input hopper of the trammel or shredder and building a drop chute on the output conveyors)
for containing aerosols based on prevailing winds and site conditions.
Aerosol control measures generally fall into three categories: a) overall control at the site; b)
grinding and screening; and c) feed inlet, product outlet, and transport. Control measures are
required at the size reduction operations as well as the conveyor or other transfer operations.
The size reduction facility must be assessed to ensure that the design, construction, product
flow, personnel flow, and overall operation contribute to the infectious carcass type and other
processing needs. The entire operation should be analyzed to determine locations and/or
activities that can contribute to carcass or cross contamination. Following are a few examples
that should be considered to contain aerosol contamination:
• Processing floor guards, baffles and separation can be achieved by adding physical
barriers, proper designing of air flows and/or flow of the operation and personnel. The
clean vs. dirty concept should include design of facilities, as well as actions taken by
maintenance, quality assurance, inspections, and flow of traffic.
• Air flow must be controlled and move through the processing facility coming in from
clean areas and moving out through dirty areas. Operations should consider the air flow
throughout the facility including air from personnel fans and ensure that air is not
carrying contamination into the exposed product.
• Air quality of make-up air pulled into the facility should be assessed for directional
source, environmental contamination potential, and appropriate filtration system.
• Roof leaks and leakages must be prevented. Continuous preventive maintenance and
quality assessment programs are critical.
• Drains must be assessed for proper construction (such as traps, blockages, breakages,
and others) and maintenance.
• Separation of welfare areas for employees (break rooms or locker rooms) from clean
areas vs. dirty areas can reduce the potential for contamination.
27
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
• Intermediate cleanings should be conducted in a manner to prevent splash and
aerosols.
• Programs should be developed to ensure that proper procedures for employee hygienic
practices, hand-washing practices, cleanliness of dress, and proper use of equipment
are followed.
• Employee training is a critical part of the success of the overall operation so that the
employees with the knowledge and the resources can perform their jobs as efficiently
and effectively as possible.
• Operations re-using water must follow USDA guidelines (9 Code of Federal Regulations
[CFR] 416.2g of Sanitation Performance Standards Compliance Guide) including
treatment to ensure that there is no introduction of pathogens. If re-use water is not
reaching a potable water standard, then it is important to ensure that this water is not
used in areas that could cause contamination of equipment, processed material, contact
surfaces or employees.
Bioaerosols, as one type of aerosol particles, are removed whenever aerosol particles as a
whole are removed or captured (Chattopadhyay, 2005). Therefore, the methodologies of
aerosol control also can be used to control bioaerosols. Many aerosol control methods such as
filtration, electrostatic precipitation, and impaction have been developed (Chattopadhyay, 2006).
However, there are differences between aerosols and bioaerosols. Bioaerosols have biological
characteristics, which means that they can grow and produce offspring even after they are
captured by conventional aerosol control methods. Bioaerosols cause secondary problems
such as generating rank odors and dispersing pathogenic spores after they are captured;
therefore, additional treatments may be necessary for biological aerosol particles. Table 9
provides some of the strategies and technologies for controlling aerosols. The strategies are
listed from the most desirable (prevention) to the least desirable (dilution) (Hartman et al.,
1997). The particulate filters have been implemented to remove microbes from the air stream,
where microbes tend to accumulate on the filter surfaces. However, microbes can later
proliferate as humidity increases. Ultraviolet germicidal irradiation has been used to inactivate
bioaerosols because bioaerosols are particularly vulnerable to damage from ultraviolet (UV)
light at 254 nm (Beggs et al., 2006). Plasmacluster ions (Sharp Corporation of Australia)
disable airborne microbes by releasing positive and negative ions into the air, and the rate of
inactivation is influenced by texture, shape, and bacterial cell wall. Electrostatic air cleaning
(electrostatic space charge system) reduces Salmonella by 77% in poultry houses (Durham,
2000). Other technologies may exist, and the cost and effectiveness of the technologies can
vary significantly.
28
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 9. Bioaerosol Control Strategies and Technologies
Strategy
Technology
Expense
Bioaerosol Control
Efficiency
Thermal with electric heating coil in
selected facility location
Very High
High
Prevention
Ultraviolet irradiation 1
High
High
Air ion emission 1
High
Moderate
Water/steam infusion
High
Moderate
Removal
Particle collectors (wet/dry)
Moderate
High
Filtration of air
Moderate
Moderate - High
Water sprays
Low
Moderate
Suppression
Wet cutting
Low
Moderate
Waterjet-assisted cutting
High
Moderate
Enclosed area
Moderate
Moderate - High
Exhaust ventilation
Low
Moderate
Isolation
Control of airflow
Separate air split
Low
Moderate
Spray fan
Low
Moderate
Air curtain
Moderate
Moderate
Dilution
Main ventilation stream
Moderate
Low
Local ventilation stream
Low
Low
1: In the ceiling of surgery rooms of hospitals and health care facilities, UV lamps are often installed and function to inactivate
nearby bioaerosols (Kujundzic et al., 2006)
2: The emission of air ions (ion density of 105-106 e* cm"3) for 30 minutes results in the removal of 97% of 0.1 |jm particles and
95% of 1 |jm particles from indoor air (Lee, 2011). The removal of aerosols by ion emission will result in bioaerosols being
transferred from the air to the ground, walls, and ceiling.
2.1.3.2 Noise Control
OSHA sets maximum noise limits to protect workers from noise-related injuries depending on
the level and duration of the noise. At levels above 85 decibels, hearing conservation
precautions must be taken with hearing protection safety equipment including ear muffs and ear
plugs. Equipment modifications to minimize impact from noise include use of enclosed cabs,
exhaust mufflers, hood over the grinder engine, and motor with sound insulation or building a
sound barrier around the size reduction unit. A buffer zone of vegetation around the facility's
perimeter also lowers the noise level to the neighborhood. Operating the machine at lower
RPM, on earth (rather than on concrete) using electric engines (instead of diesel-powered) can
reduce the noise. Rubber mats (10 millimeter thickness) can act as a noise dampening
insulation.
2.1.3.3 Minimizing Projectiles
Projectiles generated by the size reduction process can result in dispersion of pathogens, cross
contamination and impact worker protection. A tub grinder can project an object as far as 300
feet (Yepsen and Goldstein, 2009). Maintaining the curtains, wearing safety glasses and hard
hats, positioning the operator in an enclosed cab and enforcing restricted access to the
processing area can provide operator protection during operations.
Size reduction units (such as tub grinders and others) typically have features to deflect and
control projectiles. Horizontal grinders, because of their configuration, have less of a tendency
to generate flying objects. Low speed operation and a rotor design that turns down toward the
29
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
material (not upwards) can contain projectiles. Projectile control features include the direction of
rotation of the horizontal rotors, a continuous horizontal feed, containment structures, a floating
compression roll that closes automatically on lower loads and a material deflection curtain and
shear pin shutdown mechanism. A screen is erected at the front of the horizontal grinder from
Fecon, Inc. (Lebanon, Ohio) to prevent any fragments from leaving the immediate work area.
The power feeder manufactured by Rotochopper, Inc. (St. Martin, Minnesota) rises 15 inches to
minimize the chance of flying materials. Amada Machine Tools America, Inc. (Schaumburg,
Illinois) have grinders with enclosed top covers. Tub grinders manufactured by Vermeer
Corporation (Pella, Iowa) are equipped with a thrown object restraint system that reduces the
distance and amount of material ejected by the grinder by: a) a drum deflector that partially
covers the rotor or drum on the upswing, and b) a tub cover partially enclosing the top left side
of the tub. The following operations can minimize projectiles and maximize worker safety: a)
keeping the tub or feed hopper full at all times, b) avoiding the feeding of nongrindable
materials, c) maintaining grinder covers properly and using double covers or impact shields, d)
starting to load the tub grinder with prebreaker material and then loading the carcass material
that needs to be processed (this practice will cover the rotor or drum with prebreaker material
and will not allow large material to contact the rotor or drum initially), e) keeping the tub as full
as practicable to reduce the amount and distance of thrown objects, as the material itself acts
as a shield over the grinding chamber, f) before ending the size reduction operation, grinding to
be finished until the tub is approximately half full, and emptying the tub the next day by opening
it and letting the unground material fall out, and g) grinding with the tub cover and deflector in
place and over the tub.
2.1.4 Reduction in Toxicity, Mobility, or Volume through Treatment
The best available techniques (BATs) defined as the "most effective and advanced stage in the
development of an activity and its methods of operation, which indicate the practical suitability of
particular techniques for providing, in principle, the basis for emission values designed to
prevent or eliminate or where that is not practicable, generally to reduce an emission and its
impacts on the environment as a whole" (Ireland EPA, 2008). In addition to the consideration of
costs, advantages of alternatives and the precautionary and prevention measures, the
European Communities' Integrated Pollution Prevention and Control (IPPC) Directive 96/61/EC
and the Environmental Protection Agency Acts 1992 to 2007 require the determination of BAT
for the management or recycling of animal carcasses and animal waste to consider the following
items:
• the use of low-waste technology,
• the use of less hazardous substances,
• the furthering of recovery and recycling of substances generated and used in the
process and of waste, where appropriate,
• comparable processes, facilities or methods of operation, which have been tried with
success on an industrial scale,
• technological advances and changes in scientific knowledge and understanding,
• the nature, effects and volume of the emissions concerned (C02, S02, oxides of nitrogen
(NOx), and dust)
• the commissioning dates for new or existing activities,
• the length of time needed to introduce the best available techniques,
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
• the consumption and nature of raw materials (including water) used in the process and
their energy efficiency,
• the need to prevent or reduce to a minimum the overall impact of the emissions on the
environment and the risks to it, and
• the need to prevent accidents and to minimize the consequences for the environment.
The rendering process is one of the animal carcass management options that involves size
reduction, to meet the requirements of Animal By-Products (ABP) Regulation 1774/2002/EC
(Regulation No. 1774/2002 of the European Parliament and of the Council health rules related
to animal by-products not intended for human consumption). Potential process impacts of a
rendering operation on the environment are outlined in Table 10.
Table 10. Impact on Air, Water, Land, and Energy by Rendering
Range of Emission
(kg per ton of
unspecified animal
treated by rendering)
C02: 10.2-14.6
S02: 1.2-1.6
NOx: 0.51-0.59
Dust: 0.19-0.21
Water*
Consumption: 500-
10OOL/ton of carcass
materials (condensers - 200-
500 liters (L)/ton; boilers -
150-200 L/ton; and cleaning
200-300 L/ton).
Wastewater Generation:
1000-1500 L/ton. 5 kg/ton of
chemical oxygen demand
(COD), 600 g/ton of nitrogen
and 1.65 kg/ton of solids.
The waste water from the
process exhaust air treatment
can contain the following
contaminants: mercaptans <
2 g/L, hydrogen sulfide < 800
mg/L, ammonium nitrogen <
400 mg/L, volatile oils,
phenols, aldehydes, solids
and cleaning agents.
Land
Leakage from
drainage pipes
and tanks can
release biological
contaminants to
soil. In addition,
bulk storage of
fuels and other
chemicals if not
properly managed
may pose a risk of
accidental
spillages and
leaks.
Energy
Consumption*
Electricity:
Approximately 75
kilowatt hours (kWh)/ton
Heat: Approximately 775
kWh/ton
Odor abatement and
wastewater treatment:
Approximately 20 kWh
* European Commission (2005)
2.1.5 Cost
Hoque et al. (2007) defined equipment costs as the sum of the ownership and operating costs,
where ownership costs are fixed or overhead costs and independent of the amount of
equipment used. The operating costs increase in proportion to the amount of time the machine
is used. These authors calculated tub grinding (120 ton/hour) costs on an hourly basis
considering a five-year life cycle with 1750 hours per year of actual grinding operation. The
capital cost of a grinder (model 1300 Tub Grinder) was $ 535,750, amortized over 8750 hours of
machine life, the interest rate was assumed to be 8.00% per year on a declining balance, and
the insurance cost was an average rate of $2.40 per $100 per year =$12858, divided by 1750
hours. Table 11 provides an example of the hourly cost estimates of a tub grinder (Hoque et al.,
2007).
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 11. Representative Hourly Cost Breakdown of Tub Grinder Operation
Total Equipment Cost ($/hour)
Maintenance Cost ($/hour)
Purchase price
61.23
Inserts, nuts and bolts
Interest
13.26
20 inserts at $18.00 each, every 80 hours
4.50
Insurance
7.35
40 bolts at $2.40 each, every 160 hours
0.60
Subtotal (Owning Cost)
81.84
40 nuts at $2.40 each, every 160 hours
0.60
Machine maintenance
28.62
Grates (2 grates at $1000 each, every 500 hours)
4.00
Fuel cost
70.00
Hammers (20 hammers at $170 each, every 1000 hours) 3.40
Labor cost
30.00
Rakers (18 rakers at $155 each, every 500 hours)
5.58
Subtotal (Operating Cost)
128.62
Rods (8 rods at $160 each, every 2000 hours)
0.64
Total
210.46
Labor involved in changing wear parts
Estimated Cost ($/ton)
3.01
and general maintenance (at $30/hour, every 8 hours)
3.75
Grease (1 tub at $4.82 per unit, every 8 hours)
0.60
Maintenance
1 primary fuel filter at $80 each, every 200 hours
0.40
1 oil filter at $20 each, every 200 hours
0.10
2 primary air filters at $110 each, every 200 hours
1.10
2 secondary air filters at $70 each, every 200 hours
0.70
2 hydraulic filters at $65 each, every 200 hours
0.65
Miscellaneous parts (nonstandard items - such as
seal kits, bearings, etc.)
2.00
Total maintenance cost
28.62
The above table provides itemized costs in various categories including the parts to be replaced
or repaired, labor and materials for daily maintenance involving lubrication, inspection, and wear
parts. Hammer life, screen life, and rod life are dependent upon operator experience, material
being processed, screen size, climatic conditions, and methods of loading material into the tub
grinder. The fuel consumption for the 860 horsepower (hp) Caterpillar 3412 was estimated at
28 gallons per hour with estimated fuel cost of $2.50 per gallon. Labor cost including benefits
depends on the area.
Capital recovery of size reduction machinery has been estimated by Turhollow (2002) by the
following equation.
(PP-dSV) x + dsv x i
Capital recovery =
ha
where:
PP = Purchase price
dSV= is the discounted salvage value which is calculated as the percent of list price at
the end of year n by 60(0.885)n
i = interest rate
n = years of life
ha = annual hours of use.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Repair and maintenance of chippers and grinders (hammermills) can be estimated as 10
percent and 20 percent of the purchase price per year, respectively (Naimi et al., 2006).
Fuel use (gallons/hour) = 0.73 x 0.06 x 1.34 x Power (kW)
(PP+dSV)/2
Insurance and taxes = - X 1
ha
Labor cost is calculated using the following correlation assuming the benefit rate as 10 percent
and the wage rate is $20 per hour.
Labor cost = (1+benefit rate) x wage rate
The operating inputs are charged for interest on a six-month basis as per the following equation.
Interest on operating cost = (i/2) x (repair and maintenance cost + fuel cost)
Table 12 shows the hourly cost breakdown of different chippers and hammermills. Chipper cost
ranges from $157 to $161 per hour, and hammermill cost ranges from $229 to $252 per hour.
Table 12. Representative Hourly Cost Breakdown of Chipper and Hammermill Operation
Type of Size Reduction
Unit
Energy
Capital
Cost ($)
Life Time
(year)
Operating Time
(hours/year)
Hourly
Cost ($)
Drum Chipper
200
625,542
8
2,000
157
Large Disk Chipper
448
313,589
8
2,000
161
Mobile Grinder
(Hammermill)
(not self-propelled)
521.5
381,500
5
1,700
229
Mobile Grinder
(Hammermill)
(self-propelled)
521.5
471,500
5
1,700
252
A mobile size reduction processing is a self-contained trailer facility that can address small
outbreak events, or multiple units that can be used for a larger event. The trailer is normally
divided into three sections: mechanical/storage, carcass cooler, and processing area. The
design of the unit takes into consideration the need for robust construction while minimizing
weight, sanitary operations and cleanup. The cooler and processing sections are wet areas and
all materials and electrical fittings are rated for use in wet environments. The capacity of the
mobile unit can range up from 10 beef, 24 hogs, or 40 sheep per day with two operators. The
cooler in the trailer can hold up 6,000 pound of carcasses. A typical unit is equipped with a
diesel generator, water storage, hot water heater, refrigeration and tools to allow for fully self-
contained operation. Investment costs range depending on design and other supporting
facilities (such as level of processing, freezers, space, etc.). Costs of mobile units range
between $150,000 and $250,000, depending on the configuration and equipment. Additional
construction costs may be required at each site where the mobile unit is operated to address the
following issues: water sources and waste management, maintenance of the grounds
immediately surrounding the operational site, sanitary facilities and office accommodations for
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
personnel, and others. Table 13 provides the approximate costs of typical fixed and mobile size
reduction facilities.
Table 13. Estimated Cost of Fixed Plant and Mobile Unit.
Description
Fixed Plant
Mobile Unit
Footprint (square feet)
5,250
300 (34 feet long)
Number of Workers
6-10
2-4
Cost of Trailer for Carcass Hauling ($)
60,000
NA
Truck for Trailer or Mobile Unit ($)
18,000
18,000
Processing Facility Investments ($)1
525,000-2,187,000
170,000 J
Total Processing Facility Cost ($)
603,000-2,258,000
303,000 4
NA: not applicable.
1: Fixed facility price per square foot = $100-400, depending on materials used, without land acquisition costs (Hardesty et al.,
2009; Iowa State University, 2010; Irwin, 2011).
2: Land cost assumes $40,000 per acre (dependent on location) and land requirements for fixed plant and mobile unit are two
acres and one acre, respectively.
3: Gooseneck trailer (33 feet long * 8.5 feet wide * 13 feet tall) with 8.5 feet x 11 feet processing area, 8.5 feet x 11 foot holding
cooler, 8.5 foot x 10 foot mechanical room, 6000 pound cooler capacity, and F450 Ford Truck as tow vehicle costs $150,000;
and a second similar unit costs $110,000 without the tow vehicle (Sleeping Lion Associates, 2005)
4: Includes construction cost of $115,000 for the mobile unit.
A customized cost can be prepared for case specific conditions to evaluate whether it would be
better to purchase a machine or to hire the equipment to do the processing during the outbreak.
The cost estimate should include site development costs, utility hook-up fees, permits and
wastewater pre-treatment costs, and obtaining a site with appropriate zoning and municipal
services.
2.1.6 Regulatory Issues
Potential causes of mass animal mortality range from natural disasters to more complex
situations involving infectious diseases. Notwithstanding the cause, timely and effective local
response is essential to limit impact on the industry and community, and to allow for the
mobilization of resources locally and from other levels of government as required.
Communications and coordination with local and federal government play an important role as
the carcass management guidelines, if any, vary from state to state. A few examples are
indicated in Table 14. Analogous to the Resource Conservation and Recovery Act (RCRA)
definition of hazardous waste being a subset of solid waste, infectious waste is a subset of
medical waste. Local information on carcass management, state resource locators and the
American Veterinary Medical Association (AVMA) policies are available at
http://www.vetca.orq/lacd/index.cfm last accessed September 2, 2015 (Veterinary Compliance
Assistance, 2015).
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 14. Examples of Local Carcass Management Regulatory Issues.
State/
Country
Sample Disposal Issue
Reference
British
Columbia,
Canada
Guidance included for planning and response within the regional
district of Fraser-Fort George including its member municipalities
and electoral areas for dealing with mass animal carcasses
generated in an emergency and the handling of SRM.
St. John &
Associates Projects
Inc. (2009)
California
The California Department of Food and Agriculture does not regulate
carcass management for animals. Local government (county
department of environmental health) and federal agency tasked with
public health or air or water pollution are involved.
Doran (2004)
Franco (2002)
CalRecycle (2015)
Colorado
In the event of any all-hazard event that results in livestock mortality,
the Colorado Department of Agriculture shall exercise its authority
as lead agency to respond to, direct and otherwise manage any
such event.
State of Colorado
(2011)
Maine
During catastrophic events a large number of carcasses must be
managed and equipment must be brought onto the farm, biosecurity
protocols shall be established to minimize the amount of traffic on
and off the farm to ensure proper disinfection procedures are used,
and to limit exposure of livestock to off-farm traffic. In the case of a
disease outbreak, the farm operation shall contact the appropriate
state and federal animal health authorities for direction on
implementing biosecurity measures.
Maine Department
of Agriculture,
Conservation and
Forestry (2012)
Michigan
Rendering services must be provided by a licensed dead animal
dealer, rendering plant or animal food manufacturing plant.
Standard operating procedures for mass carcass management are
available at
http://www.michigan.gov/documents/mda/Mass_Carcass_279789_7.
pdf. A list of recent (2015) licensed Tenderers is available at
httD://www.michiaan.aov/documents/mdard/TransDortina Disposal
Michigan
Department of
Agriculture and
Rural Development,
2015
of Dead Animal List bv County Report Jan2015 478984 7.pdf
last accessed September 10, 2015
North
Carolina
Veterinary Division is the lead state agency to oversee animal
carcass management as regulated under existing Administrative
Rules, specifically, Subchapter 52C - Control of Livestock Diseases:
Miscellaneous Provisions, Section .0100 - Diseased and Dead
Animals. The State Health Director and by extension the Local
Health Director in each county is charged with preventing health
risks and disease and promoting a safe and healthful environment
according to NCGS 130A, Articles 1-20.
State Animal
Response Team
(2003)
Washington
The solid waste management plan considers that animal carcasses
in excess of 15 pounds are agricultural wastes. This plan allows for
burial of animal carcasses with a minimum of two feet of cover and
100 feet from any well or surface water during an emergency or
disease outbreak. All carcasses must be transported to the carcass
management site within 24 hours. Rendering should be performed
by a licensed rendering company. Incineration can be performed at
a permitted facility suited for this waste type. Composting to be
done utilizing Best Management Practices. Washington State
Department of Agriculture (2014) indicates that a carcass must be
disposed of within 72 hours of the time of death or discovery to avoid
nuisance odors ordisease. If weather conditions prevent burial
within 72 hours and rendering, composting, landfilling, or natural
decomposition cannot be accomplished, then the carcass must be
buried as soon as the weather permits.
Clark County
Department of
Environmental
Services (2015)
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Category 2 material, which includes the carcasses of animals that die on-farm, should be
treated according to Method 1 as defined in Annex IV to EU Regulation 142/2011 (i.e., 133°C /
20 min/3 bars/50 mm particle size) before being used as an organic fertilizer (Article 13 (d) of
European Commission (EC) Regulation 1069/2009) (European Food Safety Authority (EFSA),
2011). Method 1 is a sterilization process deemed to inactivate heat resistant hazards including
bacterial spores with a sufficient safety margin. This method is intended also to cover risks that
are not known until now, taking the experience of the BSE crisis into account. Indeed, Method 1
has been shown to reduce the titers of TSE agents between 2 to 3 log 10 (Schreuder et al.,
1998). Cohen et al. (2001) reported that a batch rendering system can achieve a 3.1 log
reduction (1,000-fold) in BSE infectivity, while a continuous system can reduce infectivity 2.0 log
(100-fold) to 1.0 log (10-fold). The rendering industry in the U.S. is closely regulated by state
and federal agencies, with each routinely inspecting rendering facilities for compliance to BSE-
related regulations and chemical residue tolerances. USDA's Animal and Plant Health
Inspection Service (APHIS) issues export certificates and inspects rendering facilities for
compliance to restrictions imposed by the importing country. State officials inspect and enforce
quality, safety policies, issuance of air and water quality permits and rendering licenses, and
making sure that dead or diseased animals are not illegally diverted for use in food (Hamilton et
al., 2007).
At the installation/facility level, the most appropriate techniques will depend on local factors. A
local assessment of the costs and benefits of the available options may be required to establish
the suitable option. The overall objective of ensuring a high level of protection for the
environment by appropriate management of infectious carcasses can often involve making
trade-off judgments between different types of environmental impacts, and these judgments will
often be influenced by local considerations. The obligation to ensure a high level of
environmental protection including the minimization of long-distance or trans-boundary pollution
implies that the most appropriate techniques cannot be set on the basis of purely local
considerations. The choice can be made by considering various factors including the following
areas as suggested by Ireland EPA (2008): a) the technical characteristics of the facility; b) its
geographical location; c) local environmental considerations; and d) the economic and technical
viability of upgrading existing installations. The efficient and environmentally safe treatment and
management of mass animal carcasses will require:
• early notification;
• an estimate of the scale of carcass management required;
• the selection of an appropriate carcass management methodology;
• the availability of suitable carcass management sites; and
• the timely provision of applicable resources.
Rules and regulations on facilities and equipment for meat and poultry establishments are
available (Federal Register, 1997) and may be considered as guidance in considering decisions
about design and construction of the carcass pretreatment facilities, as well as the selection of
equipment to be used in their operation. The information included in the Federal Register
(1997) was drawn from technical knowledge and experience used by the Food Safety and
Inspection Service regarding the acceptability of facilities and equipment.
The South Coast Air Quality Management District (SCAQMD) in California is proposing rule 415
to reduce public exposure to odors from rendering facilities (SCAQMD, 2015). This proposed
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
rule includes establishment of odor management practices and requirements to reduce odors
from facilities rendering animals and animal parts, odor best management practice requirements
for the transportation and handling of rendering material, and cleaning and maintenance at the
rendering plants, enclosure and odor control requirements for the receipt and processing of
rendering material and wastewater, and an odor mitigation plan for facilities with continuing odor
issues. The enclosure standards and odor control standards of the proposed rule 415
specifically indicate that the size reduction and conveying equipment, material receiving areas,
and transfer operations at a rendering facility shall not be operated except that the equipment or
process is operated in a closed system or located within the confines of a permanent enclosure.
2.1.7 Personnel Safety
The operation of heavy equipment, handling and processing require the operators and
regulators to be vigilant with regard to worker health and safety. There are specific worker
protection standards set by the federal Occupational Safety and Health Administration (OSHA)
that apply to equipment as well as the operation of the equipment. Personnel safety is an
overriding consideration during carcass treatment operations. In a treatment facility setting,
microorganisms can enter the body through the mouth, lungs, broken or unbroken skin or the
mucous membrane lining of the inner surface of the eyelids. Before commencing
treatment/processing work, personnel must be fully briefed on the nature of the disease and any
specific hygiene requirements. Safety issues to consider include personal hygiene facilities, the
availability of rescue equipment, hearing protection and protection from dust. Protective
clothing including respirators must be supplied to personnel when there is any risk to humans
from the organism involved, or if large amounts of dust or odor are generated.
The safety and security items generally include the following items:
• Warning signs,
• Prevention of visible contamination to or from the carcass surface,
• Necessary actions in the event of visible contamination,
• Notifying supervisor of abnormal events or activities that may impact product safety,
• Sanitizing of hand tools,
• Portable carcass management site lighting,
• Road pylons,
• Site marking tape, and
• Identification badges.
The personnel protective equipment (PPE) will include the following items:
• Protective clothing including footwear,
• Coveralls,
• Masks or respirators,
• Decontamination equipment and chemicals,
• Medications such as anti-virals (controlled by medical staff),
• Portable toilets,
• Temporary shower and changing facilities,
• Clothes washing facilities, and
• Walk-through footwear disinfectant facility.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
In general, for all work or all situations where contact may occur with carcasses, carcass
processing or any other potential bioaerosol source, the wearing of PPE is recommended. This
equipment for bioaerosol areas must include impermeable coveralls, with rubber gloves and
boots, a helmet and visor for dirty work, a type N-95 National Institute for Occupational Safety
and Health (NIOSH)-approved disposable respirator (Goyer et al., 2001). For damp locations, a
respirator with a valve at the center is recommended.
No employee shall operate and/or cause to be operated any machinery without proper
protective guards in place or modify/disable any protective guards on machinery without
contacting appropriate health and safety authority for such approval or implementing the
lockout/tagout program. Such guards shall be provided to protect the operator and other
employees from hazards such as exposed belts, pulleys, sheaves, drive shafts, drive couplings,
chains, rotating parts, flying chips and sparks. Special hand feeding tools for placing and
removing material shall be such as to permit easy handling of material without the operator
placing a hand in the danger zone. Such tools shall not be in lieu of other guarding required by
the pretreatment facility policy but shall be used only to supplement protection provided.
The presence of plastics and other contaminants (particularly chlorine compounds) in the
carcass feed material for the size reduction facility should be avoided to reduce the generation
of persistent organic pollutants during incomplete combustion if incineration and burning
carcass management options are considered. Use of plastic bags and similar material is
necessary for operator and animal hygiene. However, the use of plastic bags should be
minimized by use of mechanized and automatic feed devices. Methods to be considered for
safe handling and operations include: a) use of mechanized loaders to avoid contact with
carcasses; b) use of macerating and grinding techniques to allow automatic, continuous loading
and operation; and c) minimizing contamination from packaging, including use of non-
halogenated plastics (UNEP, 2006).
The storage, handling, grinding and charging equipment needs to be cleaned periodically and
usually before maintenance, by passing wood chips through the system and then incinerating
them.
The management of the facility is the key to ensuring safe and environmentally benign
operation. All personnel operating the facility shall be fully conversant with their duties, in
particular with regard to routine operation, maintenance, disease control, process upset
conditions and local environmental legislation. The competence of operators shall be
addressed by suitable training at an appropriate level for the facility.
Tools and procedures should be available to ensure the safe work environment of the workers.
Equipment and all accessories should be cleaned and sanitized or used in designated areas to
control contamination. The procedures should also address proper dress and PPE for
employees. If unexpected interruptions occur (extended mechanical downtime, complete
equipment breakdown, refrigeration failure, power outage, etc.), the facility should have
procedures in place so that these procedures can be implemented quickly. These procedures
may include availability of alternate power generators, microbiological testing of carcasses and
contact surfaces, zone cleaning and utilization of bioluminescence testing to demonstrate
sanitary conditions.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Advanced Sensors and Monitoring Systems
The capability of the microsystems in meat industries can bring new measuring or monitoring
tools that may compensate the investment effort by bringing cost cutting or creating novel added
value. A size reduction facility requires a significant quantities of water at different stages of
processing. A fast analysis of cleanliness using a disposable 'lab-on-chip' system would allow
reduction of the amount of detergent and water to a lower level while routinely checking the
efficiency and improved sanitation by providing continuous and statistical measured data
(Vivancos et al., 2012). PCR-microarray assays provide new methods for the identification of
animal-derived ingredients. For example the mitochondrial DNA (mtDNA) 16S rRNA gene can
be selected as a vertebrate molecular marker gene to detect animal-derived ingredients
including bovine, goat, pig and chicken (Delevoye, 2013). The PCR amplification and
hybridization conditions can be optimized according to the sets of species-specific microarray
probes including pairs of quality control probes designed with universal primers so that the
animal-derived ingredients can be checked rapidly and accurately. The micro-PCR chips can
also detect pathogens. Although the fast detection of microorganism methods are not allowed
by regulatory authorities, they can be used for screening of products and materials to reduce the
number of expensive tests (ACTIA, 2013). In addition, the antibody-conjugated nanoparticles
can readily and specifically identify a variety of bacteria through antibody-antigen interaction and
recognition with an extremely high fluorescent signal for bioanalysis and can easily be
incorporated with biorecognition molecules, such as antibodies. Handheld and contactless
equipment based on miniaturized sensing and detection systems can provide safe handling and
processing of infectious carcasses to analyze physical and chemical parameters. The X-ray
system can scan up to 38 tons per hour of carcasses and determine fat content and weight with
a high accuracy, while also spotting foreign objects. Metal objects as small as 0.0118 inch can
be detected with the DETECTRONIC X-ray scanners, as well as other contaminants including
bone, shell, stone, rubber, and plastic.
Size reduction of animal carcasses induces a high risk of work-related musculoskeletal
disorders, and increases the difficulty of developing efficient working assistance and security
tools for workers (Pontonnier et al., 2011). Co-manipulation (manipulation of an object
simultaneously held by a robot and a human operator) is an emerging robotics field that can
provide biosafety and security tools for musculoskeletal disorders and pathogen exposure (see
examples in Figure 3). A generic arm cobot (collaborative robot or exoskeleton-like assistance
equipment) can be used in handling and processing of carcasses to acquire parameter values
(such as volatile gas sensing, colorimetric analysis). A cobot can be worn by a worker and
assist in lifting, or the bodyweight assistant robot could also adjust the optimum working height
according to the size of the worker or other conditions.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Figure 3. Examples of Robot Integrated Sensors that Could be Adapted to Carcass
Handling and Processing Tasks
(photographs are shown with permission from Dr. Elisabeth Delevoye, Universite de Grenoble, France)
2.1.8 Community Acceptance
The pretreatment facility and its infrastructure involve interactions with the local community,
state and federal agencies. Proper pretreatment and carcass management plans for infectious
animal carcasses within an emergency management system must include consideration of the
type of event generating the deaths, environmental and regulatory factors that could complicate
carcass management efforts, logistical issues (size and scope), cost, disease biosecurity
concerns, and public perception. These issues should be integrated vertically to include
national, state, and local community and emergency responders, and horizontally to include
scientific proficiency from each of the professionals (and their respective state/federal agencies)
that will have roles in animal carcass management issues.
2.1.8.1 Media / Public Information
An effective public information strategy is an essential part of managing an emergency. The
public will demand information even if the effects of the size reduction of infected carcasses are
limited, which will put an enormous premium on what local officials say publicly and how they
say it. Negative public reaction can often be defused by an articulate, calm and confident
spokesperson who is able to reassure the public that the response is appropriate and effective.
It is expected that there will be a high demand for information throughout treatment operations.
The effective diffusion of information is particularly important as there are likely to be several
levels of responders involved. The key is to have designated public information officers and/or
spokespersons from the outset, including industry representatives, who cooperate closely with
each other. A clear, timely and consistent message is essential. Appropriate Federal, State,
and local organizations involved must ensure that the overarching requirement to deliver
information is not unduly delayed by a perceived need to assemble complete information. The
public may want to know the situation and should be briefed accordingly. An information officer
should be in the Emergency Operations Center (EOC) at all times to collect and coordinate the
information being received and to ensure that the media and public are briefed regularly and
comprehensively.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.2 Physical Inactivation
Inactivation can target the extracellular or outer surface components of microorganisms or
intercellular or inner components such as nucleic acids, with the aim of impeding the ability of
the pathogen to replicate. Inactivation technologies fall into two broad categories, namely,
physical and chemical. Physical inactivation includes application of dry heat (flaming, hot air
oven, infrared), moist heat (below 100 °C, at 100 °C, above 100 °C), ultra-high pressure steam,
energy (thermal, plasma arc irradiation, pulsed-field electricity, ultrasonic energy, UV light).
When microorganisms are exposed to UV light, dimerization of the nucleic acids occurs, thereby
impeding the ability of these microorganisms to replicate. Thermal inactivation, however, relies
on the principle that at certain temperatures, infectivity and immunogenicity of microorganisms
are lost at the same rate while at other temperatures, these properties are lost at different rates.
Sonication disrupts the morphological structure of microorganisms while retaining the
immunogenic components. The effectiveness of key physical inactivation treatment of
infectious carcasses is discussed in the following section.
2.2.1 Effectiveness
Water
The removal of pathogens from carcasses by water can sometimes be effectuated using a
rinse, spray, immersion bath or steam treatment. Only small reductions in bacterial load can be
achieved by rinsing a carcass with pure water. During immersion chilling, a substantial
decrease in contamination levels of carcasses can be expected, and the variation in the
bacterial load of individual carcasses will be reduced. The effectiveness of spraying carcasses
with cold water is not affected by the water pressure, does not decontaminate carcasses, and
aerosols that are generated may even spread microbial contamination. The decontaminating
effect of a hot water spray is partly caused by the lethal effect and partly by the detachment of
pathogens or removal together with melted softened fat. Pathogens that are attached to skin
surfaces might be more heat resistant than the pathogens that are not attached (Dickson and
Anderson, 1992). High-pressure washing of carcasses with cold water has resulted in improved
microbiological quality (Bolder, 1997). Although only a small amount of moisture was taken up
by the carcasses, pathogens might be driven into the tissue or interior areas by high pressure.
Steam can also be used for inactivation of pathogens on carcass surfaces. The advantages of
steam are the efficient heat transfer, lack of residues and an intense additional cleaning of the
surfaces. Disadvantages are the difficulties of application in a continuous production process.
Moist heat in the form of saturated steam under pressure is the most widely used and the most
dependable method for removal of pathogens from carcasses by water. Steam sterilization is
nontoxic, inexpensive, rapidly microbicidal, sporicidal, and rapidly heats. Like all sterilization
processes, steam sterilization has some deleterious effects on some materials, including
corrosion and combustion of lubricants. The basic principle of steam sterilization, as
accomplished in an autoclave, is to expose each item to direct steam contact at the required
temperature and pressure for the specified time. Thus, there are four parameters of steam
sterilization: steam, pressure, temperature, and time. Specific temperatures must be attained to
ensure the microbicidal activity.
Microwave Inactivation
Microwave inactivation is essentially a steam-based process, since inactivation occurs through
the action of moist heat and steam generated by microwave energy. A microwave system
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
consists of a chamber into which the electromagnetic spectrum is directed from a microwave
generator (magnetron). Typically, two to six magnetrons are used with an output of
approximately 1.2 kW each. Some systems are designed as batch processes and others are
semi-continuous. The treatment system consists of a charging system, hopper, shredder,
conveyor screw, steam generator, microwave generators, discharge screw, secondary
shredder, and controls. The equipment includes hydraulics, high-efficiency particulate air
(HEPA) filter, and microprocessor-based controls protected in a steel enclosure.
Gamma Irradiation
Irradiation with a low dose of y-rays is more successful than some of the chemical treatments
such as glutaraldehyde or chlorine. Gamma irradiation provides a number of benefits in cost
and sterility assurance. It can be applied under safe, well-defined, and controlled operating
parameters, and is not a heat- or moisture-generating process. Consequently, there is no heat
stress and condensate drainage and outgassing is not required. Most importantly, there is no
residual radioactivity after irradiation. Electron accelerators do not require isotopes, but need
high energy levels up to 10 megaelectron volts (MeV) and permit an effective penetration of
radiation into the product of only 1-2 cm (Corry et al., 1995). This type of pretreatment is
insufficient for the overall inactivation of whole carcasses, although superficial contamination will
be eradicated.
Electron Beam Radiation
A beam of high-energy electrons from an electron gun is propelled at high speed to strike
against a target. Typically, e-beam systems consist of a power supply; a beam accelerator
where the electrons are generated, accelerated, and directed towards the target; a scanning
system that delivers the required dose; a cooling system to cool the accelerator and other
assemblies; a vacuum system to maintain a vacuum in the accelerator; a shield to protect
workers; a conveyor system to transport the carcasses; and sensors and controls. The
shielding system could be in the form of a concrete vault, an underground cavity, or an integral
shield around the treatment area. E-beams do not alter the physical characteristics of the
carcass material except perhaps to raise the temperature a few degrees.
Plasma Technology
Plasma is matter that contains partially or wholly ionized gas with a net neutral charge and is
often referred to as the fourth state of matter as it shares properties similar to both those of
gases and liquids. Plasma is created by energy deposition into a gaseous mixture. Gas turns
into plasma due to ionization, dissociation and excitation of the bound states of atoms and
molecules of the background gas. Therefore, plasma consists of a gaseous mixture of charged
particles (free electrons and ions) and neutral activated species including gas molecules, free
radicals, metastables and ultraviolet photons. Energetic electrons generate intensively
numerous chemical active species due to collisions between atoms and molecules. In the gas
mixture containing oxygen and water vapor, most of the primary radicals are O and OH. Cold
plasma produces (gaseous) activated ions, photons, electrons and free radicals, collectively
termed plasma, that exert their effects at 30 to 60 °C; hence, the term 'cold' or non-thermal.
Plasma may inactivate both vegetative cells and bacterial endospores (Aly and El-Aragi, 2013).
Synergistic effects between these possible mechanisms of inactivation can be expected,
depending on the operational conditions and the design of the plasma generator. Plasma has
been used for management of some waste streams in the past, but has not been demonstrated
on animal carcasses at the field scale.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Pulsed-field Electricity
Pulsed-field electricity is used for the electrostimulation of carcasses in the cattle industry.
Research has shown that the treatment also causes a reduction in bacterial counts and
prolongation of the lag phase of bacterial growth (Bawcom et al., 1995).
Ultrasonic Energy
The application of ultrasonic energy to carcasses is possible when they are immersed in water;
application is therefore suitable only for small carcasses that can be immersed. The inactivation
effect is due to cell disruption, which can be amplified by the combination method of physical
and chemical treatment (such as altering the pH and temperature or by chlorination). The
presence of fat may reduce the effectiveness of the technique as sonication can be inhibited by
the presence of organic material.
Ultraviolet Light
UV light can be used to inactivate pathogens present on the surface of the carcasses, to
decontaminate water, and to control the pathogen aerosolized in the atmospheric light in the
storage and processing areas. UV radiation has several potential applications, but unfortunately
its germicidal effectiveness and use is influenced by organic matter; wavelength; type of
suspension; temperature; type of microorganism; and UV intensity, which is affected by distance
and dirty tubes. Its use on carcass surfaces can be ineffective if the skin surfaces are highly
irregular, with hair and feather follicles causing shadow areas that cannot be reached by the UV
light. Bacteria and viruses are more easily killed by UV light than are bacterial spores.
Thermal Processes
Thermal processes are those that rely on heat (thermal energy) to destroy pathogens in the
carcass material. This category can be subdivided into low-heat, medium-heat, and high-heat
thermal processes. Low-heat thermal processes (93 °C - 177 °C) are those that use thermal
energy to inactivate the carcass material at temperatures insufficient to cause chemical
breakdown or to support combustion or pyrolysis. The two basic categories of low-heat thermal
processes are: a) wet heat treatment that involves the use of steam and is commonly done in an
autoclave; and b) dry heat (hot air) processes where no water or steam is added. Instead, the
waste is heated by conduction, natural or forced convection, and/or thermal radiation using
infrared heaters. Medium-heat thermal processes take place at temperatures between 177 °C
to 370 °C and involve the chemical breakdown of organic material. The key processes are
reverse polymerization using high-intensity microwave energy and thermal depolymerization
using heat and high pressure. High-heat thermal processes generally operate at temperatures
ranging from approximately 540 °C to 8,300 °C or higher. Electrical resistance, induction,
natural gas, and/or plasma energy provide the intense heat. High-heat processes involve
chemical and physical changes to both organic and inorganic material resulting in total
destruction of the carcass material. Operating costs, including electricity and consumables
(plasma torches have a limited life span), may be significant. Many units are still in the
development phase and some technologies may not be fully commercialized.
The agents causing TSEs vary in their resistance to inactivation by physical agents. In general,
TSE agents are much more resistant than conventional infectious agents such as bacteria and
viruses to heat, ultraviolet radiation, ionizing radiation and microwave irradiation. Ionizing,
ultraviolet and microwave irradiation have little effect on transmissible degenerative
encephalopathies (TDEs) and have no practical application in their inactivation (Taylor, 2000).
A small fraction of hamster-passaged scrapie TDE (strain 263K) infectivity survived exposure to
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
dry heat at 360 °C for 1 hour, but the brain homogenate had been lyophilized and was heated
under anoxic conditions. Drying of scrapie-infected tissue is known to enhance its
thermostability (Asher et al., 1987). In contrast, when 7-mg samples of nonlyophilized,
macerated, ME7-infected mouse-brain were exposed to dry heat, there was no detectable
infectivity after an exposure to 200 °C for 1 h, even though some infectivity survived exposure to
160 °C for 24 hours or 200 °C for 20 min (Taylor, 2000). However, 263K and 301V partially
survived exposure at 200 °C for 1 hour (Taylor, 2004).
2.2.2 Impact on Environment
Odors can be a problem around autoclaves if there is insufficient ventilation. If the carcasses,
debris and other materials are not properly segregated to prevent hazardous chemicals from
being fed into the treatment chamber, toxic contaminants will be released into the air or
condensate, or in the treated waste. If proper precautions are taken to exclude hazardous
materials, the emissions from autoclaves are minimal. Many autoclave manufacturers offer
many features and options such as programmable computer control, tracks and lifts for carts,
permanent recording of treatment parameters, autoclavable carts and cart washers.
E-beam systems do not create any pollutant emissions except possibly for small amounts of
ozone which breaks down to 02. The residual ozone helps remove odors and contributes to the
disinfection process in the treatment chamber, but it should be converted back to 02 before
being released into the environment or workspace. The waste residue looks exactly as it did
before treatment, since e-beam irradiation does not change the physical characteristics of the
waste. Therefore, a mechanical process is needed to render the treated waste unrecognizable
and reduce volume. E-beam systems may contain lead (Pb) in the shielding; the Pb should be
recycled or treated as hazardous waste after the e-beam unit is decommissioned.
High-heat thermal processes predominantly involve pyrolysis (not combustion or burning).
Pyrolysis involves a set of reactions different from incineration and hence, different gaseous
products and waste residues are produced. In many cases, pollutant emissions from pyrolysis
units are at levels lower than those from incinerators. Waste residues may be in the form of a
glassy aggregate or carbon black. The high heat needed for pyrolysis can be provided by
resistance heating, plasma energy, induction heating, natural gas, or a combination of plasma,
resistance heating, and superheated steam. Pyrolysis systems are a relatively new technology
and require careful evaluation. Different plasma technology designs have varying emission
characteristics but have emissions that are generally lower than the emissions from traditional
incinerators. Despite plasma systems having lower emissions than traditional waste
incinerators, plasma technologies may still emit dioxin, which has been linked to serious health
problems, including cancer. Because of the high energy consumption with plasma systems, the
treatment facility should consider total environmental impact to include not just emissions on-
site (including pollutants from any co-generation or flaring of the off-gases) but also
environmental emissions associated with high electrical usage, i.e., off-site emissions
contributed by electric power generating stations. Flaring the off-gas adds to the environmental
pollution. The system and equipment design should incorporate a heat recovery process (such
as a heat exchanger to obtain steam or hot water) using the product gas. Vendors may indicate
the possibility of recycling the carbon black (as a tire filler) or glassy waste residues (as roadbed
or construction aggregate). A technical and economic feasibility study should be conducted, if
the concept is found to be beneficial, an implementation plan should be developed.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
A carcass treatment facility should consider discharges or emissions (including fugitive
emissions) to all possible environmental media (workplace air, outside air, waste residues, and
wastewater) and select technologies with the least impact on the environment. All liquid
discharges after treatment should meet requirements set by the local publicly owned treatment
works (POTW) or National Pollutant Discharge Elimination System (NPDES) permits, if
discharging directly into surface streams. Solid waste residues should pass the EPA's toxicity
characteristic leaching procedure (TCLP) to be disposed at a municipal solid waste landfill.
2.2.3 Implementability
Barriers to direct steam exposure or heat transfer (such as inefficient air evacuation; excessive
carcass mass; bulky materials with low thermal conductivities; or waste loads with multiple
bags, air pockets, sealed heat-resistant containers, etc.) may compromise the effectiveness of
the system to inactivate the material. Air evacuation is more effective in autoclaves with a pre-
vacuum cycle or multiple vacuum cycles. With higher vacuum levels and more vacuum cycles,
the heat penetration is deeper and the heating of the waste load is more uniform. Certain load
configurations such as multi-level racks with sufficient spaces between to allow more surfaces
to be exposed to steam are more efficient than other configurations such as tightly stacked
containers. The treatment facility should define a standard load and waste configuration for
which specific time-temperature parameters can achieve a specific kill. Operators should
monitor carcass load sizes, load configurations, containment and other conditions that may
result in less-than-optimal heating conditions. Whenever those less-than-optimal conditions
arise, exposure times and steam temperatures should be increased to provide a margin of
safety. Continuous monitoring of temperature during the exposure time and at various points in
the chamber is important in detecting heating problems. Records of chemical or biological
indicator tests, time-temperature profiles, maintenance activities (such as replacing filters and
gaskets), and periodic inspections should be maintained. Advanced autoclave systems may
contain combine steam treatment with pre-vacuuming and various kinds of mechanical
processing before, during, and/or after steam inactivation. The combinations include: a)
vacuum/steam treatment/compaction, b) steam treatment-mixing-fragmenting /
drying/shredding, c) shredding/steam treatment-mixing / drying (and chemical cleaning), d)
shredding-steam treatment-mixing / drying, e) steam treatment-mixing-fragmenting/drying, f)
pre-shredding/stream treatment-mixing, and g) shredding/steam treatment-mixing-compaction.
Each of these systems operates differently. Nevertheless, they treat the same types of carcass
materials and have emission characteristics similar to an autoclave.
2.2.4 Reduction in Toxicity, Mobility, or Volume through Treatment
While size reduction (shredding or grinding) reduces the volume of the treated waste by 60 to
80 percent, high-heat thermal processes reduce volume by 90 to 95 percent. Pathogens are
not expected to survive under the very high temperatures. However, even with extremely high
temperatures, the heat transfer characteristics in a plasma chamber may not necessarily mean
uniform heating at elevated temperatures.
2.2.5 Cost
The cost of physical inactivation technologies varies widely. In general, the capital cost of
steam-based technologies is lower than the capital cost of high heat thermal systems.
Approximate capital costs of equipment and accessories, representative vendors, typical
installation and energy requirements, and capacities are shown in Table 15. These technology
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
descriptions are based on vendor information (such as vendor websites, brochures, and
personal communications), non-proprietary technical data provided by vendors or
manufacturers, evaluations by non-profit institutions and private consultants, research by
academic institutions, government studies, and other sources. An effort was made to
corroborate or verify the accuracy of vendor information where possible. Claims by vendors that
were deemed misleading or dubious were omitted from the descriptions. The information
presented is intended to provide an overview and general understanding of these technologies.
While there may be other manufacturers in the market, there was no attempt to make this list
comprehensive. As noted earlier, mention of a specific technology in this report should not be
construed as an endorsement by the author or by the Agency.
Table 15. Costs of Selected Physical Inactivation Pretreatment Technologies
for Carcasses
Technology*
Vendor
Installation Requirements
Capacity
(lb/hour)
Capital
(Operating)
Cost ($)
Autoclave
Bondtech (Somerset,
Kentucky)
Steam - 152 °C/55 psig; drain;
Electricals
250-6000
100,000-
275,000
Mark-Costello (Carson,
California)
Steam - 60 psig; electrical - 115
V/1-phase 5A; Small and medium
units -100 lb of steam/cycle; large
standard units -150-200 lb/cycle.
225-3000
36,000-
61,000
Tuttnauer
(Ronkonkoma, New
York)
Steam - 137 °C/33 psig; equipped
with microcomputer-based
controls.
Up to 1500
130,000-
250,000
Autoclave-
Grinder-Crusher
Enviro-Safe Treatment
Solutions, LLC
(Covington, Indiana)
Temperature up to 133 °C/45 psi;
onboard Clean-in-Place system to
prevent spread of disease;
mobilization time approximately
three weeks.
8000
($0.29 per
pound)
Pregrinder/Shred-
der-Heat
Treatment-Liquid
Effluent
Decontamination-
Electrical
Generator- Steam
Generator
BioSAFE Engineering
(Brownsburg, Indiana)
10,000 Ib/hr steam; 350 kWh
electricity; 31,200 gallons/day
water for steam; 105 gallons/h
diesel for steam and electricity.
Mobile units with integrated control
system can be rented. Set-up and
mobilization time: <8 h, each.
20,000
(14-16
bovines/h)
1.6 M
($0.04 per
pound to
$0.08 per
pound)
Vacuum-Steam-
Compaction
San-I-Pak (Tracy,
California)
Steam - 1-inch insulated line 65
psig (minimum) to 125 psig
(maximum);
Water - 30-100 psi.
25-2240
30,000-
500,000
Steam-Mixing-
Fragmenting/
Drying/
Shredding
Tempico (Madisonville,
Louisiana)
Steam - 450 Ib/h at 60 psig; water
- 75 gpm; electricity - 30 kWh,
250 A; air - 5 cfm at 100 psig.
300-750
400,000 and
above
Shredding/Steam-
Mixing/Drying,
Chemical
Sterile Technologies
Inc. (West Chester,
Pennsylvania)
NA
600-4000
367,000-
427,000
Shredding-Steam-
Mixing/Drying
Antaeus Group (Hunt
Valley, Maryland)
Hot and cold water; Electrical -
480 V, 60 Hz, 3-phase; Installation
takes about 8 hours.
150
250,000
Shredding-Steam-
Mixing/Drying
Ecolotec (Union Grove,
Alabama)
Electrical - 230 V 200 A
disconnect, 115 V 60 A breaker;
Steam - less than 80 Ib/h at 60
psi; Cold water - 10 gpm,
Ventilation - 10 air exchanges/hr.
300
350,000
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Technology*
Vendor
Installation Requirements
Capacity
(lb/hour)
Capital
(Operating)
Cost ($)
Steam-Mixing-
Fragmenting/
Drying
Hydroclave Systems
Corp. (Kingston,
Ontario, Canada)
Electrical - 460 V, 3-phase, 60 Hz
for drive motor; depending on
model. Steam - 40 to 60 psi
minimum; Water consumption -
100 to 1,000 gallons per batch;
Condenser water flow - 10 to 40
gpm
200-2000
250,000-
600,000
Microwave
T reatment
Sanitec (West Caldwell,
New Jersey)
Electrical - 460/480 Vac; 150 to
200 A, 60 Hz, 3-phase; Water-
3/4" NPT hookup. 0.1 kWh per
pound of waste treated; peak
demand - about 70 kW.
220-550
500,000-
600,000
Dry Heat
T reatment
KC MediWaste (Dallas,
Texas)
Electrical - 480 V, 3-phase, 125 A;
Compressed air - 100 scfm and
90 psig at peak; Water - 5 gpm at
60 psig. Energy consumption
about 63 kWh per hour.
200
400,000
Pyrolysis-
Oxidation
Oxidation Technologies
(Annapolis, Maryland)
Electrical - 480 V, 3-phase; Water
- 5 to 10 gpm when needed;
Compressed air - 100 psig. 0.6-
1.2 kWh per pound of waste
treated. 80% of the heat is
recovered as hot water or steam.
100-1500
1.6 M-3.3 M
Plasma Pyrolysis
Electro-Pyrolysis, Inc.
(Wayne, Pennsylvania)
112 to 2250 kW power and water
for cooling.
750
0.6 M - 1.2 M
HI Disposal Systems
(Indianapolis, Indiana)
Processing chamber at about
1,650 °C and uses a 2 MW
plasma arc torch.
3000
3 M
Vance IDS/Bio Arc
(Largo, Florida)
A hopper, shredder, two
processing chambers, rollers, heat
recovery system, inert gas
generation system, residue
collection, scrubbers, PLC controls
with communications, and safety
and shutdown systems.
400
800,000
Induction-Based
Pyrolysis
Vanish
Technologies/LFR
(Raritan, New Jersey)
Electrical induction coil
surrounding a tube furnace heats
the walls of the tube to 982 °C.
The waste is conveyed through
the tube using an internal rotating
screw or auger.
280
1.1 M - 2.0 M
Advanced
Thermal Oxidation
NCE Corporation
(Carrollton, Texas)
Loader, shredder, primary and
secondary chambers, cooling
chamber, a 30 hp turbo fan, liquid
mist injectors, and liquid filtration
system. Volume and mass
reductions 97% or more may be
achieved.
200
800,000
Electron Beam
BioSterile Technology
(Fort Wayne, Indiana)
85 sq. ft. floor space and standard
208 V, 3-phase electrical power.
Energy consumption 0.035
kWh/hour
400-550
400,000
Electron Beam-
Shredding
University of Miami E-
Beam (Coral Gables,
Florida)
380/220 VAC, 40 A, 3-phase.
Energy consumption is 0.04
kWh/pound of waste treated.
400
1.2 M
*: Combinations of physical and other technology packages are included. Note: Facilities should check with vendors to get the latest
and most accurate prices. NA: not available. NPT: National Pipe Thread. PLC: programmable logic controller VAC: Volts alternating
current.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.2.6 Regulatory Issues
Infectious disease transmission has four requirements: a pathogen must be present; a sufficient
number and virulence of pathogens to cause infection must also be present; a susceptible host
must be available; and a pathogen-specific, appropriate portal of entry into the susceptible host
must exist or be created. EPA encourages treatment of regulated infectious waste, which is a
subset of medical waste, as early in the waste management chain as possible. The definition of
treatment is stated in the Medical Waste Tracking Act (1988) as follows:
40 CFR 259.30 (b)(1)(iv) - "Ensure that the concentration of microorganisms capable of causing
disease in humans is reduced so as to render such waste as non-infectious or less infectious
and, thus, safer to handle, transport, and dispose of. However, the waste need not be sterilized.
The treatment processes commonly available are not 100% effective in inactivating
microorganisms. Complete inactivation is unnecessary, since any refuse is expected to support
some level of bacterial activity. Destruction of the waste is satisfied when the waste is ruined,
torn apart, or mutilated so that it is no longer recognizable as medical waste."
For those states that were covered by the Medical Waste Tracking Act, manifesting regulated
waste was not necessary if it could be determined that all of EPA's concerns, biological and
physical hazards and aesthetic degradation had been accomplished (DiDomenico, 1992). The
main purpose for the treatment technology is to inactivate infectious carcasses by destroying
pathogens. Facilities should make certain that the technology can meet state criteria for
disinfection. Many states require approval of alternative technologies based on microbiological
inactivation efficacy (Health Care without Harm, 2001). A consortium of state regulatory
agencies called the State and Territorial Association on Alternative Treatment Technologies
(STAATT) developed consensus criteria for the levels of microbial inactivation (Bauch, 2000):
Level I: Inactivation of vegetative bacteria, fungi, and lipophilic viruses at a 6 log 10
reduction or greater
Level II: Inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites,
and mycobacteria at a 6 log 10 reduction or greater
Level III (selected as the recommended minimum criteria): Inactivation of vegetative
bacteria, fungi, lipophilic/hydrophilic viruses, parasites, and mycobacteria at a 6 log 10
reduction or greater; and inactivation of B. stearothermophilus spores and B. subtilis spores
at a 4 log 10 reduction or greater
Level IV: Inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites,
and mycobacteria, and B. stearothermophilus spores at a 6 log 10 reduction or greater.
A 6 log 10 reduction (or a 106 kill) is equivalent to a one millionth survival probability in a
microbial population or a 99.9999 percent reduction of the given microorganism as a result of
the treatment process. The following representative biological indicators were recommended by
STAATT: mycobacteria (such as mycobacterium phlei and mycobacterium bovis BCG American
Type Culture Collection (ATCC) 35743) - 6 log 10 reduction; bacterial spores (such as B.
stearothermophilus ATCC 7953 and B. subtilis ATCC 19659) - 4 log 10 reduction. Technology
vendors may be able to provide documentation showing that their technology can meet
applicable state regulations. If no documentation is available, the facility can request that
efficacy testing be conducted using an independent qualified laboratory.
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The OSHA requirements for worker safety must be followed at the treatment facility. Periodic
general safety inspections including checks based on OSHA regulations and other applicable
codes (such as adherence to the electrical code) must be performed. Calibration and checking
on function of testing equipment must be conducted regularly.
2.2.7 Personnel Safety
Worker training, including a basic understanding of steam-based treatment systems, standard
operating procedures, occupational safety (e.g., ergonomics, proper waste handling techniques,
hazards associated with steam and hot surfaces, blood splatter or aerosolized pathogens, etc.),
record-keeping, identifying waste that should not be treated in the unit, recognizing heating
problems, dealing with unusual carcass loads and other less-than-optimal conditions, periodic
maintenance schedules, and contingency plans (e.g., what to do in case of a spill or power
outage) should be provided.
2.2.8 Community Acceptance
A plume of smoke or colored liquid from a facility will be a public concern regarding that facility's
environmental impact on the surrounding community. Hazardous-release emergency response
and hazard communication are covered by the Emergency Planning and Community Right-to-
Know Act (EPCRA). A program to inform and discuss physical inactivation technology with the
local community is important since many of these processes are not well-known. Choosing a
cleaner inactivation technology demonstrates the commitment to protecting public health and
the environment. Some vendors represent their technologies as noiseless and odor-free. The
best way to evaluate this is to observe the technology during actual operation, either at the
manufacturing facility or preferably, at an installation facility. Reducing noise and noxious odors
are important aspects of occupational health and community relations. Siting of a new system
may be hampered by a lack of public acceptance, especially if the site is located near
residences, schools, and sensitive populations. Treatment processes with which the public is
familiar such as microwave or steam systems may be accepted by the community more readily
than lesser known technologies such as plasma and electron beam technologies. A program to
inform and engage the community in the selection of an alternative technology, allowing the
community an opportunity to provide input into the decision-making process, would result in
greater community satisfaction and improved standing of the health care facility as an
environmental leader in the community.
2.2.8.1 Media / Public Information
Because of the dynamic nature of an emergency response to an event, the catastrophic
mortality treatment must be implemented in an effective manner relative to the ever-changing
understanding of the nature and extent of the disease in question. To allow the mortality
management teams to respond quickly to changing field conditions, communication between the
teams and incident command must be maintained through the chain of command. Real-time
communication and pre-shift meetings constitute the required communication needed to support
catastrophic mortality management associated with an outbreak or other natural disaster
resulting in large scale livestock loss.
2.3 Chemical Inactivation
This section of this report will discuss chemical inactivation of carcasses. The principles of
sterilization, disinfection and decontamination are integral processes in the pretreatment of
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
carcasses and associated contaminated material. The principles of sterilization, disinfection
and decontamination are defined as the principles essential for reducing the risk of transmission
within containment zones, to the environment, and within the community.
Sanitation is a heat treatment at lower temperatures over an extended period of time.
Sterilization is an absolute process that completely eliminates all living microorganisms. The
probability of a microorganism surviving a sterilization process is considered to be less than one
in one million (i.e., 10"6), and is referred to as sterility assurance. Given that toxins and prions
are not living microorganisms, the concept of sterilization does not apply. Disinfection is a less
lethal process than sterilization that eliminates most forms of living microorganisms. The
effectiveness of the disinfection process is affected by a number of factors, including the nature
and quantity of microorganisms, the amount of organic matter present, the type and state of
items being disinfected, and the temperature. Decontamination is the process by which
materials and surfaces are rendered safe to handle and reasonably free of microorganisms or
toxins. The primary objective of decontamination is to protect containment zone personnel and
the community from exposure to pathogens that may cause disease. Depending on the
situation, decontamination may require disinfection or sterilization. Decontamination procedures
represent a critical containment barrier; failure in the procedures can result in occupational
exposure to, or the unintentional release of, infectious material or toxins.
The effectiveness in reduction of pathogens in both processes is affected by temperature, a
factor that generally cannot be controlled when used under emergency conditions. Animal
carcasses are not always completely heat-treated to eliminate pathogen survival and/or re-
growth. This lack of complete heat treatment justifies the need for post-process disinfection with
appropriate chemicals. Chemicals in solid, liquid, or gaseous matrices could be used to
inactivate pathogens prior to or during pretreatment (such as composting and anaerobic
digester) of large infectious animals in case of a catastrophic event. The amount of disinfectant
chemicals should be at a sufficient level to inactivate the pathogens by the following
mechanism: a) interaction with a microbial surface; b) penetration into microorganisms; and c)
action at the target sites. The key four factors to be considered when selecting appropriate
chemicals are: 1) pathogen inactivation efficacy, 2) potential health effects, 3) environmental
effects, and 4) availability and cost.
Given the wide variety of biological toxins and their considerable differences in physical
properties, it is impossible to provide a standardized set of chemical decontamination
parameters that apply to all circumstances. The facility where the toxins are handled and/or
stored needs to ascertain the risks and determine how best to mitigate them, including
appropriate and effective inactivation technologies.
2.3.1 Effectiveness
The selection of a chemical inactivation agent is dependent on a variety of factors, including the
resistance of the pathogenic material or toxin, the application (e.g., liquid or gaseous), and the
nature and type of surfaces to be treated (such as hard surface, porous materials, organic/fatty
tissue - hydrophobic, etc.), concentration of chemical inactivation agent, contact time,
temperature, relative humidity, pH and stability. Table 16 describes the influence of chemical
inactivation agents on pathogens on carcasses. The susceptibility ranking of microorganisms
with respect to chemical inactivation agents is shown in Table 17.
50
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
There are many types of pathogens including protozoa, helminths, prions, viruses, fungi, algae,
mycobacteria, bacteria, and viroids, but relatively few are directly connected to diseases. Some
pathogens change their forms under some circumstances. Certain bacteria and fungi form
spores under low-nutrient or dry conditions. Protozoa form oocysts and cysts dependent on
their life cycle, while helminths form eggs. After an animal infection, viruses inject their genome
into host cells. Among viruses, there are many types such as i) bacteriophages, which infect
bacteria, ii) viroids, which are only RNA, devoid of proteins, that infect higher plants causing
crop diseases and iii) animal viruses. Animal viruses are divided into two groups: non-
enveloped and enveloped. Besides viruses, prions (proteinaceous infectious particles) cause
diseases that have been classified as slow viral diseases. Prions are important, because they
are the most difficult pathogen to inactivate.
51
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 16. Influence of Chemical Inactivation Agents on Pathogens in Carcasses.
Chemical Inactivation Agent
Acids
(Hydrochloric
acid,
Acetic acidr
Citric acid)
Alcohols
(Ethyl alcohol,
Isopropyl alcohol)
Aldehydes
(Formaldehyde,
Paraformaldehyde,
Gl literal dehyde)
Most susceptible
Alkalis
(Sodium or
ammonium
Hydroxide,
Sodium
carbonate)
Biguanldes Halogens Oxidizing Agents Phenolic Quaternary
(chiorhexidirve, Hypochlorite Iodine (Hydrogen peroxide, Compounds Ammonium
Nolvasan, Peroxyacetic acid, XmnhvrCompounds
chlorhex, T rifecta nt, Virkort-S, TekTrol' (Roccal, Zepharin,
Virosan, Oxy-Sept 333) Pheno-Tel* II) DiQuat, Parvosol,
Hibistat) D-256)
Mycoplasmas
~
EE
EH I
X
E
33 1
X
E
I
i
i
EX
D
¦
Gram-positive bacteria
~
a
EH
~
B
B
1
E
X
Gram-negative bacteria
D
ED EE
0
I
I
D
¦
B
B
m
D
¦
Pseudomonads
D
:
[
i
D
s
D
B
B
EE
B
¦
Rickettsiae
3
¦¦
~
~
~
s
~
¦
B
B
~
E
¦
"
Envelopedvi ruses
a
D
t
i
~
s
D
¦
B
B
s
9
¦
_
Chlamydiae
9
G
D
0
s
D
B
B
B
B
¦
:
¦
Non-enveloped viruses
¦
D
B
B
~
B
D
¦
S
B
B
H
¦
Fungal spores
¦
9
g
B
9
¦
_
Picornaviruses (i.e. FMD)
¦
Q
n
B
~
IS
IS
¦
13
B
13
D
¦
¦
Parvoviruses
¦
a
SI
B
a
CI
a
¦
b
9
J
B
¦
:
Acid-fast bacteria
¦
a
D
B
0
B
~
B
0
S
B
:
Bacterial spores
9
B
B
~
B
D
B
B
'
B
B
¦
Coccidia
¦
a
Prions
¦
B
Most resistant
9 EE Highly effective
w H Effective
ui —
No activity
Q Limited activity ^ Information not available
a -Varies with composition
b-Peracetic acid is sporicidal
c-Ammonium hydroxide
d - Some have activity against Coccidia
52
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 17. Ranking Susceptibility of Pathogens in Carcasses,
Ranking of
Susceptibility
Pathogen
Chemical Inactivation Agent
Extremely resistant
Prions
• Unusually resistant to chemical disinfectants
• High concentrations of sodium hypochlorite
(NaOCI) or heated strong solutions of sodium
hydroxide (NaOH)
Highly resistant
Protozoal oocysts
• Ammonium hydroxide, halogens (high
concentrations), halogenated phenols
Bacterial endospores
• Some acids, aldehydes, halogens (high
concentrations), peroxygen compounds
Resistant
Mycobacteria
• Alcohols, aldehydes, some alkalis, halogens,
some peroxygen compounds, some phenols
Non-enveloped viruses
• Aldehydes, halogens, peroxygen compounds
Susceptible
Fungal spores
• Some alcohols, aldehydes, biguanides,
halogens, peroxygen compounds, some
phenols
Gram-negative bacteria
• Alcohols, aldehydes, alkalis, biguanides,
halogens, peroxygen compounds, some
phenols, some quaternary ammonium
compounds
Gram-positive bacteria
Enveloped viruses
Highly susceptible
Mycoplasma
• Acids, alcohols, aldehydes, alkalis,
biguanides, halogens, peroxygen
compounds, phenols, quaternary ammonium
compounds
Prion diseases are transmissible protein misfolding disorders in which misfolding of a host-
encoded prion protein (PrP) occurs. PrP may exist in two forms: a normal cellular prion protein
designated as PrPc and a pathogenic misfolded conformer designated as PrPSc (see Figure 4).
The superscript (Sc) has been used to refer to scrapie, the first and the most ancient animal
transmissible spongiform encephalopathy (TSE). The etiology and animal hosts for these
disease variants are shown in in Table 18.
pleated sheet
Figure 4. A normal prion (left) and a disease-causing prion (right).
53
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 18. Etiology of Animal Prion Diseases and Typical Inactivation of Prions
Disease Host Etiology Inactivation*
NaOCI (2%, 20 °C, 1 h)
NaOH (1 N, 20 °C, 1 h)
Autoclave under soaked conditions in water
(134 °C, 18 min)
Alkaline detergent (1.6%, 43 °C, 15 min)
Phenolic disinfectant (5%, 20 °C, 30 min)
3% sodium dodecyl sulfate, 100 °C, 10 min
7 M guanidine hydrochloride (room
temperature, 2 h)
3 M guanidine thiocyanate (room
temperature, 2 h)
3 M trichloroacetic acid (room temperature,
2 h)
60% formic acid (room temperature, 2 h)
50% phenol (room temperature, 2 h)
Enzymatic detergent (0.8%, 43 °C, 5 min) +
hydrogen peroxide gas plasma sterilization
(1.5 mg/L, 25 °C, 3 h)
Vaporized hydrogen peroxide (2 mg/L, 30
°C, 3 cycles)
* Tateishi et al., 1991; Fichet et al., 2004; Sakudo et al., 2011.
Prions, the etiologic agents of bovine spongiform encephalopathy and scrapie, are exceptionally
resistant to chemical disinfectants, especially if prions are in the tissues. Prions are not
considered living organisms because they are misfolded protein molecules that may propagate
by transmitting a misfolded protein state. In general, prions are quite resistant to proteases,
heat, radiation, and formalin treatments, although their infectivity can be reduced by such
treatments (Qin et al., 2006). Table 18 provides examples of inactivation of prions. Whenever
possible, two or more methods can be combined to ensure the inactivation of prions. Effective
decontamination of prions relies upon protein hydrolysis or reduction or destruction of protein
tertiary structure. Examples include bleach, caustic soda, strongly acidic detergents (Race and
Raymond, 2004), and pressurized steam autoclave at 134 °C for 18 minutes has been found to
be somewhat effective in deactivating the agent of disease (Brown et al., 2000; Collins et al.,
2004). Ozone sterilization is currently being studied as a potential method for prion
denaturation and deactivation: 2-log10, 3-log10, and 4-log10 inactivation by ozone dosage of 7.6
to 25.7 mg/liter with contact times of 5 seconds and 5 minutes) (Ding et al., 2013). North
Carolina State University, the Central Institute for Animal Disease Control in the Netherlands,
and BioResource International North Carolina) have demonstrated the effectiveness of a
bacterial enzyme called keratinase that can fully degrade a prion or protein particle. Langeveld
et al. (2003) and Shih and Wang (2008) reported the effects of keratinase on brain tissues from
cows with BSE and sheep with scrapie. Their results showed that, when the tissue was
pretreated and in the presence of a detergent, the enzyme fully degraded the prion, rendering it
undetectable.
Autoclaving at 134 °C for 1 hour (i.e., single-step inactivation process) or a chemical treatment
with 1 N NaOH or NaOCI followed by autoclaving at 121 °C for 1 hour (i.e., two-step process) is
acceptable for prion inactivation (Government of Canada, 2013). A solution of 2.5% NaOCI and
Scrapie
Sheep,
Goats
Infection with Prions •
of unknown origin •
Transmissible mink
encephalopathy
(TME)
Mink
Infection with Prions •
of either sheep or
cattle origin ,
Chronic wasting
disease (CWD)
Cervids
Infection with Prions ,
of unknown origin .
Bovine spongiform
encephalopathy
(BSE)
Cattle
Infection with Prions •
of unknown origin
Exotic ungulate
spongiform
encephalopathy
(EUE)
Nyala,
Kudu
Infection with Prions ,
of BSE origin
Feline spongiform
encephalopathy
(FSE)
Cats
Infection with Prions •
of BSE origin •
TSE in non-human
primates (NHP)
Lemurs
Infection with Prions
of BSE origin •
54
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
0.25 N NaOH, with a contact time of at least 30 minutes, will permit adequate inactivation of
most biological toxins, including peptide toxins and mycotoxins (Wannemacher and Wiener,
1997). However, these inactivation measures will reduce prions but may be incompletely
effective if dealing with high titer material, when pathogen is protected within dried organic
matter or inside the tissue.
2.3.2 Impact on the Environment
Several of the chemical inactivation agents pose significant potential safety hazards for workers
and other ecological habitats, if released to the environment. Capture and treatment of residual
chemicals in water, solids, and air are necessary. Inactivation agents are classified by their
chemical nature and each class has its unique characteristics, hazards, toxicities and efficacy
against various pathogens. Environmental conditions such as the presence of organic matter,
pH or water hardness can also impact the action of chemical inactivation agents. Therefore,
before using any chemical disinfectant, the label instructions should be followed thoroughly.
Most of these chemicals can cause irritation to eyes, skin and/or the respiratory tract of
operating personnel. Therefore, the safety of all workers should be considered.
Environmental factors can greatly impact the effectiveness of a pretreatment process. Carcass
composition and surface properties (such as organic load, surface topography), operating
conditions (temperature, relative humidity, pH, water hardness or the presence of other
chemicals) are all important environmental factors to consider. Additional environmental factors
include runoff, leakage, and residues from the processing unit. Many chemicals are known for
their ecological hazards on plants and aquatic life (i.e., sodium carbonate, hypochlorites,
phenolics, and others). Therefore, drainage, runoff, biodegradability, and the appropriate
treatment needs should be considered.
2.3.2.1 Wastewater Treatment
Effluent treatment systems should be designed to treat liquid waste at 134 °C for 1 hour
(Government of Canada, 2013). Precautions should be taken when autoclaving chemically
treated (e.g., NaOH, NaOCI) waste as many of the chemical inactivation agents can be
damaging to equipment and other exposed surfaces. Proper material for the construction of the
containers and surface coatings should be used. In addition, personnel should be cautious
when handling hot NaOH (post-autoclave) to prevent potential exposure to NaOH vapor.
Liquid effluent treatment systems are designed to prevent the release of untreated materials into
sanitary sewers and the environment (Government of Canada, 2013). An effluent treatment
system is required for the liquid waste material generated from operation and handling of non-
indigenous animal pathogens and prion areas. Effluent treatment systems may also be a
design consideration for other containment zones, depending on the activities undertaken and
the pathogens being handled. The liquid waste effluent from sources within or serving the
containment zone, including sinks, showers, toilets, autoclaves, washing machines, and floor
drains, is also treated. Effluent treatment systems are commonly heat-based. However, a
chemical-based system may be practical on a smaller scale where small volumes of liquid
effluent require treatment.
Liquid waste is collected in a large stirred tank in traditional effluent treatment systems. When
the tank is full, the liquid is heated or chemically treated and, after a sufficient period of time and
once treatment is complete, the tank is drained. Achieving a uniform temperature or chemical
55
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
concentration in a large tank can be a challenge, which can lead to inadequate pathogen
inactivation. To mitigate this risk and maintain a uniform temperature, stirrers or paddles are
used to ensure constant mixing of the effluent in a steam jacket that surrounds the effluent
vessel shell. In contrast to the stirred tank, the effluent can be collected continuously in a large
tank and streamed through a retention pipe where the effluent is heated (e.g., to approximately
150 °C) for a specific period of time through a continuous effluent treatment system. In a stirred
tank or a continuous effluent treatment system, the key process parameters (e.g., time,
temperature) must be verified against the infectious material or toxins of concern. The internal
temperature and pressure of the effluent and the decontamination time should be recorded
throughout the cycle. In addition, the treatment system must be equipped with alarms to permit
failure detection. The effluent treatment system should be configured as fail-safe to ensure no
untreated waste leaves the system (World Organization for Animal Health, 2009). Liquid waste
released from the effluent treatment system has to meet all local and applicable environmental
regulations and bylaws (provisions related to temperature, chemical/metal content, suspended
solids, oil/grease, and biochemical oxygen demand). Chemical residues (e.g., chlorine and
ozone), if any, need to be neutralized prior to release because they can generate noxious fumes
and water-borne residues or by-products that can be harmful to aquatic animals and humans if
inhaled, absorbed or ingested. With other types of treatment such as heat, post-treatment
cooling of the treated wastewater may be required before discharge. Efforts should be made to
minimize the quantity and load of wastewater generated. Treatment of the wastewater can be
performed by following the BAT guidance (Ireland EPA, 2008): a) prevent wastewater
stagnation; b) perform initial screening of solids using sieves; c) remove fat from wastewater,
using a fat trap; d) use a flotation method with the use of flocculants to remove surface solids; e)
provide wastewater holding capacity in excess of routine requirements; f) prevent liquid
seepage and odor emissions from wastewater treatment tanks by sealing their sides and bases
and either covering them or aerating them; g) remove nitrogen and phosphorus through the use
of combined oxidation, nitrification and denitrification processes; h) conduct laboratory analyses
of the effluent composition regularly and i) maintain records.
Generally, the range of pathogens in sludge arising from the treatment of carcass processing
waste will be similar to the pathogens in sewage sludge, so the requirements for inactivation in
terms of heat and/or pH will be similar, although the process parameters to achieve stabilization
may differ because of the nature of the waste (Carrington, 2001). The waste produced during
the pretreatment of carcasses may contain prions. Gale and Stanfield (2001) reported that
treatment of sludge by using lime could potentially destroy at least 90% of BSE agents. Brown
et al. (1986) reported alkaline treatment (pH 12) gives a 1-log destruction of sheep scrapie
agent after 1 hour exposure. Gale and Stanfield (2001) added quicklime or hydrated lime to
raise the pH to greater than 12 for a minimum period of 2 hours and reported that this type of
enhanced sludge treatment by lime may destroy the BSE agent. Kemp (2010) reported
treatment with alkali (calcium hydroxide in the form of hydrated lime to maintain a pH of 8.5 to
13) and heat (temperature in the range of 60 °C. to 99 °C) eliminates or reduces TDE such as
BSE, Creutzfeldt-Jacob Disease and scrapie.
2.3.3 Implementability
Application of chemical inactivation agents to disinfect infectious animal carcasses require
biological risk management protocols to prevent, contain and eliminate the spread of disease in
case of an outbreak situation. Inactivation protocols may vary, depending on the need of the
56
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
situation. Additionally, the health and safety of personnel and animals are always an important
consideration. No single chemical inactivation agent is adequate for all situations. A
comparison of key characteristics and considerations of commonly used chemical compounds is
shown in Table 19. The use of trade names in Table 19 does not in any way signify
endorsement of a particular product. The trade names for some of the chemicals are only
provided as examples. For an effective inactivation protocol, consideration should be given to
the pathogens (i.e., bacteria, viruses, fungi, or prions) being targeted during an infectious
disease outbreak, the characteristics of a specific chemical compound, and environmental
issues. In general, Gram-positive bacteria are more susceptible to chemical inactivation agents
while mycobacteria or bacterial endospores are more resistant. The hydrophilic, non-enveloped
viruses (adenoviruses, picornaviruses, reoviruses, rotaviruses) are more resistant to disinfection
than lipophilic, enveloped viruses (coronaviruses, herpes viruses, orthomyxoviruses,
paramyxoviruses, and retroviruses) (see Table 20). Pathogens also vary in their ability to
survive or persist in the environment (i.e., debris). These pathogens can also be effective at
creating a biofilm that enhances their ability to persist in the environment and avoid the action of
chemical compounds. Application of surfactants, mechanical scrubbing, brushing and scraping
during processing can help reduce biofilm. These issues are important considerations when
selecting a chemical compound and protocol to use. Whenever possible, identification of the
target pathogen should be done. However, if the pathogen has not been identified, a broad-
spectrum approach should be utilized until identification can be made.
57
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 19. Characteristics and Considerations for Selected Chemical Inactivation Agents
Chemical
Categories
Alcohols
„0_
R H
Aldehydes
0
I u I
R H
Biguanides
NH NH 1
Halogens:
Hypochlorites
"O-CI
Halogens/Halides
Oxidizing
Agents
Phenols
Quaternary
Ammonium
Compounds (QACs)
Chemical/
Trade Names
Ethyl alcohol,
Isopropyl alcohol
Formaldehyde
Glutaraldehyde
Chlorhexidine
Nolvasan®
Virosan®
Bleach
Betadyne
Providone®
Hydrogen peroxide
Peraceticacid
Virkon SR
Oxy-Sept 333'—'
One-Stroke Environ
Pheno-Tek II®
Tek-Trol®
Roccal®
DiQuat®
D-256
Mechanism
of Action
•Precipitates
proteins
•Denatures lipids
•Denatures proteins
•Alkylates
nucleic acids
•Alters membrane
permeability
•Denatures proteins
•Denatures proteins
•Denature proteins
and lipids
• Denatures proteins
• Alters cell wall
permeability
• Denatures proteins
• Binds phospholipids of cell
membrane
Advantages
•Fast acting
•Leaves no residue
•Broad spectrum
•Broad spectrum
•Broad spectrum
•Short contact time
•Inexpensive
•Stable in storage
•Relatively safe
•Broad spectrum
• Good efficacy with
organic material
• Non-corrosive
• Stable in storage
• Stable in storage
• Non-irritating to skin
• Effective at high temperatures and
high pH (9-10)
Disadvantages
•Rapid evaporation
•Flammable
•Carcinogenic
•Mucous membranes
and tissue irritation
•Only use in well
ventilated areas
•Only functions in
limited pH range
(5-7)
•Toxic to fish
(environmental
concern)
•Inactivated by sunlight
•Requires frequent
application
•Corrodes metals
•Mucous membrane and
tissue irritation
•Inactivated by QACs
•Requires frequent
application
•Corrosive
•Stains clothes and treated
surfaces
•Damaging to some
metals
• Can cause skin and
eye irritation
Precautions
Flammable
Carcinogenic
Not to mix with acids;
toxic chlorine gas
will be released
May be toxic to
animals, especially
cats and pigs
Vegetative
Bacteria
Effective
Effective
Effective
Effective
Effective
Effective
Effective
Yes - Gram Positive
Limited - Gram Negative
Mycobacteria
Effective
Effective
Variable
Effective
Limited
Effective
Variable
Variable
Enveloped
Viruses
Effective
Effective
Limited
Effective
Effective
Effective
Effective
Variable
Non-enveloped
Viruses
Variable
Effective
Limited
Effective
Limited
Effective
Variable
Not Effective
Spores
Not Effective
Effective
Not Effective
Variable
Limited
Variable
Not Effective
Not Effective
Fungi
Effective
Effective
Limited
Effective
Effective
Variable
Variable
Variable
Efficacy with
Organic Matter
Reduced
Reduced
NA
Rapidly reduced
Rapidly reduced
Variable
Effective
Inactivated
Efficacy with
Hard Water
NA
Reduced
NA
Effective
NA
NA
Effective
Inactivated
Efficacy
with Soap/
Detergents
NA
Reduced
Inactivated
Inactivated
Effective
NA
Effective
Inactivated
NA: Information not found
58
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected.
Virus Family
(relative size)
SS = single stranded
DS = double stranded
E =
5 8
5
Virus (Disease)
Animal Species
Affected
DNA Virus Families
Adenoviridae
80 - 100 nm
DS linear
Bovine adenoviruses A. B. C
Canine adenovirus (infectious canine hepatitis)
Caprine adenovirus
Equine adenoviruses A, B
Fowl adenoviruses A - E
Human adenoviruses A - F (respiratory and/or ocular disease)
Ovine adenoviruses A, B, C
Porcine adenoviruses A, B, C
Cp
ES_
NHP
Asfarviridae
175 - 215 nm
DS linear
African swine fever
Circoviridae
17 - 22 nm
SS circular
Chicken anemia virus
Porcine circovirus
Psittacine beak and feather disease virus
Hepadnaviridae
42 nm
partial DS
Hepatitis B virus
NHP
Herpesviridae
150 - 200 nm
DS linear
Alcelaphine herpesvirus-1 (malignant catarrhal fever)
Avian herpesvirus 1 (infectious laryngotracheitis)
Bovine herpesvirus 1 (infectious bovine rhinotracheitis)
B, Cv
Bovine herpesvirus 2 (pseudo-lumpy skin disease, bovine mammillitis)
Bovine herpesvirus 3/ bovine cytomegalovirus
Canine herpesvirus 1, 2 (hemorrhagic disease of pups)
Caprine herpesviruses 1, 2
Cp
Equine herpesvirus 1 (equine viral rhinopneumonitis; equine abortion)
Eq
Equine herpesvirus 2
Eq
Equine herpesvirus 3 (equine coital exanthema)
Eq
Equine herpesvirus 4 (equine viral rhinopneumonitis)
Eq
Feline viral rhinotracheitis virus
Human herpes simplex virus 1
NHP
Human herpes simplex virus 2
Human herpesvirus 3/ varicella-zoster virus (chicken pox, shingles)
Human herpesvirus 4/ Epstein Barr virus
Human herpesvirus 5/ human cytomegalovirus
A = avian; B = bovine; Bt = bat; Cp :
O = ovine; P = porcine; Diseases in
= caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R = rodent; NHP = non-human primate;
RED or with a O = Foreign Animal Diseases
59
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected (continued)
ss
Virus Family
(relative size)
single stranded DS =
double stranded
Foreign Animal
Disease (for US)
Zoonotic (Z)
Virus (Disease)
Animal Species
Affected
Herpesviridae
(continued)
Human herpesviruses 6, 7 (roseola infantum)
Ictalurid herpesvirus 1 (channel catfish virus disease)
Fish
Koi herpesvirus disease
Fish
Marek's disease virus
A
Oncorhynchus masou virus disease (or salmonid herpesvirus type 2 disease)
Fish
Ovine herpesvirus-1
O
Ovine herpesvirus-2 (malignant catarrhal fever)
B, Cp, Cv, O, P
Porcine herpesvirus 2/ porcine cytomegalovirus
P
Pseudorabies virus (Aujeszky's disease)
B, C, Cp, F, O, P
Iridoviridae
125 - 300 nm
DS linear
Epizootic haemotopoietic necrosis (EHN)
Fish
Largemouth bass disease
Fish
Papovaviric
ro)
ae
Bovine papillomavirus
B
Equine papillomavirus
Eq
45 - 55 nm
DS circular
Human papillomavirus
Parvoviridae
Adeno-associated viruses 1-6
0
B19 virus
Canine minute virus/ canine parvovirus 1
C
Canine parvovirus 2 ("parvo")
C
18 - 26 nm
SS linear
Feline panleukopenia virus (Feline parvovirus)
F
Porcine parvovirus
P
1
'
21
Poxviridae
k
J
ri
z
Bovine papular stomatitis virus
B
z
Contagious ecthyma/contagious pustular dermatitis/orf virus
C, Cp, Cv
z
Cowpox virus
B, F, R
\
Feline pox virus
F
Fowlpox virus
A
Lumpy skin disease virus
B, Bf
z
Monkeypox virus
NHP, R
z
Pseudocowpox virus (milker's nodules)
B
SO X 200 X 200 nr
DS linear
Sheep and goat pox viruses
Cp, O
Smallpox virus (Variola)
Swinepox virus
P
z
Vaccinia virus
B, L, P
A = avian; B = bovine; Bt = bat; Cp = caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R = rodent; NHP = non-human primate;
O = ovine; P = porcine; Diseases in RED or with a 0 = Foreign Animal Diseases
60
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected (continued)
Virus Family
(relative size)
SS = single stranded DS =
double stranded
Virus (Disease)
Animal Species
Affected
RNA Virus Families
Arenaviridae
Lassa virus
Lymphocytic choriomeningitis virus
10 - 300 nm
SS linear segments
Machupo virus (Bolivian hemorrhagic fever)
NHP, R
C, NHP, P, R
NHP, R
Iridoviridae
Equine arteritis virus (equine viral arteritis)
Lactate dehydrogenase elevating virus
Porcine respiratory and reproductive syndrome virus
125 - 300 nm
DS linear
Simian hemorrhagic fever virus
Eq
NHP
Astroviridae
Avian nephritis viruses 1, 2
Bovine astrovirus
Feline astrovirus (gastroenteritis)
Ovine astrovirus (gastroenteritis)
45 - 55 nm
DS circular
Porcine astrovirus (porcine acute gastroenteritis)
Turkey astrovirus (poultry enteritis and mortality syndrome)
Birnaviridae
Infectious bursal disease virus
18 - 26 nm
SS linear
Infectious pancreatic necrosis (IPN) (hemorrhagic kidney syndrome)
Fish
Akabane virus (Akabane/congenital arthrogryposis-hydronencephaly)
Cache Valley virus
Bunyaviridae
California encephalitis virus
Crimean-Congo hemorrhagic fever virus
Hantaviruses (various serotypes)
250 X 200 X 200 nm
DS linear
Jamestown Canyon virus
La Crosse virus (La Crosse encephalitis)
Nairobi sheep disease virus
Rift Valley fever virus
B, Cp, O
B, O
A, B, C, L, O
Cv
Cp, Cv, R
Cp, O, R
B, C, Cp, F, O
Caliciviridae
Bovine enteric calicivirus
Canine calicivirus
Feline caliciviruses (upper respiratory disease)
Fowl calicivirus
Hepatitis E virus
Noroviruses (Norwalk and Norwalk-like viruses)
Porcine enteric calicivirus
30 - 38 nm
SS linear
Rabbit hemorrhagic disease virus
San Miguel sea lion virus
Vesicular exanthema of swine virus (vesicular exanthema)
B
Other, P
B, Eq, NHP, P
A = avian; B = bovine; Bt = bat;
primate; O = ovine; P = porcine;
Cp = caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R :
Diseases in RED or with a O = Foreign Animal Diseases
rodent; NHP = non-human
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected (continued)
Virus Family
(relative size)
SS = single stranded DS =
double stranded
roreign Ammai
Disease (for US)
Zoonotic (Z)
Virus (Disease)
Animal Species
Affected
Avian infectious bronchitis virus
A
fYirnnavirirlap
Bovine coronavirus
B
Canine coronavirus
C
Feline enteric coronaviruses
F
Feline infectious peritonitis virus
F
Human coronaviruses (colds)
Porcine epidemic diarrhea virus
P
80
- 160 nm
Porcine hemagglutinating encephalomyelitis virus
P
linpar
z
Severe acute respiratory syndrome (SARS) virus
F
Transmissible qastroenteritis (TGE) virus
P
Turkev coronavirus fbluecomb disease')
A
Filoviridae
(D
z
Ebola virus
NHP
790 - 970 X 80 nm
SS linear
(D
z
Marburg virus
NHP
Border disease virus
O
Bovine viral diarrhea (BVD) viruses 1, 2
B
(D
Classical swine fever virus (hog cholera)
P
Fla\/i\/irirlap
(D
z
Dengue virus
NHP
Hepatitis C virus
^N\
(D
z
Japanese encephalitis virus
A P
J
(D
z
Louping ill virus
A,B, C, Cp, Cv, Eq, O, P,R
(D
z
Murray valley encephalitis virus
A B, C, Eq
45 - 60 nm
(D
z
Omsk hemorrhagic fever virus
R
SS linear
z
St. Louis encephalitis virus
A Eq
(D
z
Tick-borne encephalitis viruses (various subtypes)
B, C, Cp, O, R
(D
z
Yellow fever virus
NHP
(D
z
Wesselsbron virus
B, Cp, O
z
West Nile Virus (WNV) (West Nile fever)
A Eq
Nodaviridae
Viral encephalopathy and retinopathy (viral nervous necrosis)
Fish
30 nm
SS linear
A = avian; B = bovine; Bt = bat; Cp = caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R = rodent; NHP = non-human
primate; O = ovine; P = porcine; Diseases in RED or with a O = Foreign Animal Diseases
62
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected (continued)
Virus Family
(relative size)
SS = single stranded DS =
double stranded
roreign Ammai
Disease (for US)
N*
u
'¦M
O
C
O
O
N
Virus (Disease)
Animal Species
Affected
Infectious salmon anemia
Fish
Orthomyxoviridae
z
Influenza virus A:
A. Ea. F. Fr. P
z
Avian influenza
A Eq, P
Equine influenza
Eq
z
Swine influenza
A P
Human influenza
Fr, P
80
-120 nm
z
Influenza virus B: (human influenza)
Fr
bb linear segments
Influenza virus C: (human influenza)
P
(D
z
Avian paramyxovirus type 1 (Newcastle disease)
A
Avian paramyxoviruses 2-9
A
Paramvxoviridae
Bovine respiratory syncytial virus fBRSV)
B. O
Canine distemper virus
C, Fr
Canine parainfluenza virus
C
(D
z
Hendra virus
Bt, Eq, F
Human parainfluenza viruses 1-4
Measles virus
NHP
Mumps virus
(D
z
Nipah virus
Bt, C, Cp, Eq, F, O, P
150 - 300 nm
Parainfluenza 3 virus
B, O
SS linear
(D
Peste de petitis ruminants virus
Cp, O
Respiratory syncytial virus
(D
Rinderpest virus
B, Cp, O, P
Avian enteroviruses (encephalomyelitis, hepatitis)
A
Bovine enteroviruses
B
Bovine rhinoviruses
B
Hicornaviriaae
z
Encephalomyelocarditis virus (encephalomyelocarditis)
NHP, P, R
Equine rhinoviruses 1, 2
Eq
'—
(D
Foot and mouth disease virus¥
B, Ca, Cp, Cv, O, P
z
Human hepatitis A virus
NHP
28 - 30 nm
SS linear
Human rhinoviruses
Poliovirus
(D
Porcine enteroviruses (porcine enteroviral encephalomyelitis/Teschen-Talfan
disease')
P
(D
z
Swine vesicular disease virus
P
Reoviridae
(D
African horse sickness viruses 1-10
Eq
v ^ ,,
Avian orthoreoviruses
/\
Bluetongue viruses 1-24
B, Cp, Cv, O
z
Colorado tick fever virus
R
60 - 80 nm
Epizootic hemorrhagic disease viruses
B, Cv, O
DS linear segments
Rotaviruses, group A to F (rotaviral gastroenteritis)
B, Eq, L, O, P, R
A = avian; B = bovine; Bt = bat; Cp = caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R = rodent; NHP = non-human
primate; O = ovine; P = porcine; Diseases in RED or with a O = Foreign Animal Diseases
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 20. Selected Viral Families, Virus and Species Affected (continued)
ss
Virus Family
(relative size)
= single stranded DS =
double stranded
roreign Ammai
Disease (for US)
Zoonotic (Z)
Virus (Disease)
Animal Species
Affected
Avian leukosis virus
A
Bovine immunodeficiencv virus
B
Bovine leukemia virus (BLV)
B
Retroviridae
Caprine arthritis-encephalitis virus
Cp, O
Equine infectious anemia virus (EIA)
Eq
Feline immunodeficiency virus (FIV)
F
Feline leukemia virus (FeLV)
F
Human immunodeficiency viruses (HIV-1, HIV-2)
80 - 130 nm
2 copies SS linear
Human T-lymphotropic viruses 1, 2
Maedi-visna virus (ovine progressive pneumonia)
Cp, O
Ovine pulmonary adenocarcinoma virus (pulmonary adenomatosis)
Cp, O
Simian immunodeficiency virus
NHP
Simian leukemia viruses 1-3
NHP
Rhabdoviridae
(D
Bovine ephemeral fever virus
B
Infectious hematopoietic necrosis (IHN)
Fish
z
Rabies
All mammals
s
Spring viremia of carp
Fish
nmiiiirm^
z
Vesicular stomatitis virus (Indiana 1 and New Jersey subtypes)
B, Cp, Eq, O, P
180 X 75 nm
(D
z
Vesicular stomatitis virus (Indiana 2 and 3 subtypes)
B, Cp, Eq, O, P
SS linear
Viral hemorrhagic septicemia (Egtved disease)
Fish
Togaviridae
z
Eastern equine encephalitis (EEE) virus
A, Bt, Eq, P, R
Rubella virus
z
Venezuelan equine encephalitis (VEE) virus
A Eq, R
70 nm
Spring viremia of carp
Fish
SS linear
z
Western equine encephalitis (WEE) virus
A Eq
A = avian; B = bovine; Bt = bat; Cp = caprine; Cv = cervine; Eq = equine; Fr = ferret; L = lagomorph; R = rodent; NHP = non-human
primate; O = ovine; P = porcine; Diseases in RED or with a O = Foreign Animal Diseases
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Careful consideration of the characteristics of a chemical are essential to select the most useful,
effective and cost-effective product. An ideal chemical is one that has a broad spectrum of
inactivation capacity, works in any environment and is non-toxic, non-irritating, non-corrosive
and relatively inexpensive (Table 21).
Table 21. Properties of Ideal Chemical Inactivation Agent
Properties
What does it mean?
Broad spectrum
Should have a wide antimicrobial spectrum
Fast acting
Should produce a rapid kill
Not affected by environmental factors
Should be active in the presence of organic matter/fatty tissues
and compatible with other chemicals encountered in use
Nontoxic
Should not be harmful to the operator
Surface compatibility
Should not corrode (or cause the deterioration of) machine
surfaces and instruments
Residual effect on treated surfaces
Should leave an antimicrobial film on the treated surface
Easy to use
Should have label with directions to apply
Odorless
Should have a pleasant odor or no odor to facilitate its use
Economical
Should not be cost-prohibitive
Solubility
Should be soluble in water
Stability
Should be stable in concentrate and use-dilution
Cleaner
Should have good cleaning properties
Environmentally friendly
Should not damage the environment
Unfortunately, no chemical inactivation agent is ideal (Grooms, 2003). Possible causes of
inactivation failure include the following: a) over-dilution of disinfectant during pre-mixing or
application; b) incomplete or inadequate mixing; c) poor chemical penetration or coverage, d)
insufficient contact time on surfaces; and e) inadequate temperature and humidity while the
material is being applied. Failure can also result from neutralization of the chemical due to the
presence of residual liquids before the chemical was applied. Another example is to select a
product that is ineffective against the contaminating organisms present (or suspected). The
entire process must be repeated if test samples indicate that pathogens have survived the
chemical inactivation procedure.
2.3.3.1 Concentration of Chemical Inactivation Agent
Use of the proper concentration of a chemical is important to achieve the best results for each
situation. Certain chemicals may be more effective at higher concentrations, and these levels
may be limited by the degree of risk to personnel, surfaces or equipment, as well as the cost of
the chemical. However, over-dilution of a product may render the disinfectant ineffective
against the target pathogen. The product label may list the best concentration to use for
common situations.
2.3.3.2 Application Method
There are a variety of ways to apply chemical inactivation agent ranging from solid addition and
mixing to fumigation. Carcass surfaces, equipment, or infrastructures may be treated with a
chemical solution by wiping, brushing, spraying, misting, immersion, or fumigation, and
application should be conducted as recommended on the product label. Application should
occur in a systematic manner to ensure all areas are treated adequately. Ensuring the
necessary contact time is essential and surfaces must remain in contact with inactivation agent
during this process. Mechanical scrubbing and scraping may be necessary to remove oils,
grease, or exudates. Porous, uneven, cracked, or pitted surfaces can hide microorganisms and
are difficult to treat. High pressure systems can be effective for porous surfaces. However, in
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
cases of highly infectious or zoonotic pathogens, high pressure systems should be avoided or
used with caution to avoid further dispersal of the pathogen or risk to the applicator. If
appropriate, porous surfaces can be soaked in a container of chemical at the desired
concentration. Gaseous or vaporous products (for application techniques such as fumigation)
can be used in appropriate situations (such as in an enclosed chamber) and/or in combination
with a physical inactivation technology (such as ultraviolet light) can be used for treating porous
surfaces.
In a cold environment, building/areas should be heated (approximately 68 °F) since some
chemicals are less effective or ineffective at low temperatures. Following application, rotating
parts and machinery (pressure sprayers and pumps), if any, should be cleaned properly to
remove potentially corrosive chemicals. Cleaning and disinfection supplies (e.g., towels, mops)
should be treated as biohazardous waste and discarded or properly disinfected before removal
from the pretreatment facility.
2.3.3.3 Contact time
The contact times vary for chemicals to kill or inactivate pathogens. The minimum contact time
needed is normally stated on the product label. Carcass treatment should be performed with
the chemicals to achieve the desired contact time. Certain chemicals may require application
under wet conditions. Processing of carcasses by chemical activation under wet conditions
should be conducted to avoid drying before the end of the optimum contact time. Certain
chemicals may have residual activity (such as quaternary ammonium compounds, QACs) while
others may evaporate quickly (such as alcohols).
2.3.3.4 Stability and storage
Chemicals (such as sodium hypochlorite) lose stability quickly after being prepared for use or
when stored over long periods, especially in the presence of heat or light. Safety Data Sheets
(SDSs) and/or product labels will list the shelf life of the concentrated product. To maximize
stability and shelf life, products should be stored in a dark, cool location and preferably in stock
concentrations. Use of an outdated or inactivated product may result in the use of a non-
efficacious product and will lead to a false sense of security.
2.3.3.5 Temperature
Most chemical inactivation agents work best at temperatures above 68 °F. Elevated
temperatures may aid in microorganism destruction; however, higher temperatures may also
accelerate decomposition or evaporation of a chemical, thereby reducing the necessary contact
time and efficacy. Heat may also impact the carcass. Cold weather (low temperatures)
generally reduces the efficacy of chemical products. Additionally, chemical solutions may
freeze outdoors under low temperature conditions.
2.3.3.6 pH
The pH or hydrogen ion concentration of the processed carcass surface can influence both the
microorganism and the chemical agent. This effect can alter the charge on the outer surface of
the microbe. The pH can also change the degree of ionization of a chemical product, thereby
impacting efficacy. For example, the efficacy of glutaraldehyde is dependent on pH, working
best at a pH greater than 7. In contrast, quaternary ammonium compounds have the greatest
efficacy at a pH of 9-10. The pH can also affect the activity of phenolics, hypochlorite, and
iodine compounds.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
2.3.4 Control Measures for Chemical Inactivation Agents
The primary consideration is to adopt appropriate preventive measures such as elimination or
substitution of chemical inactivation agents, if possible, to directly remove the hazards at the
source. A chemical product or process can be replaced by a safer product or process that
eliminates or minimizes the risks to an acceptable level. If such measures are not possible,
segregation of the chemicals or the processes or other control measures should be taken. The
use of PPE should be considered only as a supplementary means or as the last resort to
minimize workers' exposure to the hazards. Safety measures can be achieved by engineering
and administrative controls. Engineering control measures such as installation of suitable types
of ventilation can eliminate or lower the level of chemical concentration in the air at the source.
Administrative control measures such as implementation of safe work practices and scheduling
of breaks or rotating shifts can limit worker time spent near the hazard, thus reducing worker
exposure. The adoption of good housekeeping practices could not be more emphasized when
chemicals are concerned.
2.3.4.1 Engineering Control
Ventilation is one of the effective engineering means to prevent accumulation of vapors of
chemicals or mixtures of chemicals in the processing area. There are two types of ventilation:
general dilution ventilation and local exhaust ventilation. Whatever the type, ventilation should
be used together with other methods of control to strengthen the safety protection. Attention
must be paid to the relevant environmental protection requirements in the discharge of exhaust
air to prevent contamination of the outside environment. Enclosure is an alternative means to
contain hazardous substances or work processes if the substance and process cannot be
eliminated or substituted. Neat or higher concentrations of toxic chemicals could be handled
(such as by dilution) in a closed glove box. Isolation is a safety measure to control exposure to
hazards. Personnel could be isolated from a hazardous working environment by engineering
control measures (such as an isolation booth). Engineering and work-practice controls that can
be used to resolve chemical vapor issues include ducted exhaust hoods, air systems that
provide 7-15 air exchanges per hour (the American Institute of Architects recommends no fewer
than six air exchanges per hour, and the Association for the Advancement of Medical
Instrumentation recommends 10 air changes per hour) (Rutala and Weber, 2008), ductless
fume hoods with absorbents for the chemical vapor, tight-fitting lids on immersion baths,
personal protection (such as nitrile or butyl rubber gloves but not natural latex gloves, goggles)
to minimize skin or mucous membrane contact. If engineering controls fail to maintain levels
below the ceiling limit, the treatment facility can consider the use of respirators (e.g., a half-face
respirator with organic vapor cartridge or a type "C" supplied air respirator with a full face-piece
operated in a positive pressure mode.
2.3.4.2 Administrative Control
Administrative control measures include arrangement of work schedules and stipulation of safe
work practices so that the risk of exposure of individual employees to chemical products can be
reduced. Employers should ensure that these control measures are incorporated into the
management system as far as practicable. Typical safe work procedures that reduce the
worker's exposure to chemical products should include the following:
• Ensuring the time spent near the hazard is kept to minimum;
• Keeping containers of chemicals closed when not in use;
• Avoiding skin contact with chemical disinfectants;
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
• Keeping a minimum amount of chemicals for use in the workplace, usually no more than
a half-day's or one shift's supply; and
• Adopting general practices of good housekeeping.
2.3.5 Cost
Economic considerations are always important when selecting a chemical. Since chemical
compounds vary in cost, contact time and dilution, costs should always be calculated on per
gallon of use/dilution rather than the cost of the concentrate. However, chemical inactivation
protocols are generally a cost-effective means of reducing pathogens. For example, a QAC that
costs $68.00 per gallon of concentrate will cost $0.27 per diluted gallon (0.5 ounce concentrate
per gallon of water). Considering that a gallon of diluted QAC approximately covers 100-150
square feet, the cost for inactivating a 500 square foot surface is $1.35.
A summary of representative chemical inactivation technologies and comparative rankings for
specific criteria is shown in Table 22. The rankings are for comparative purposes only for each
criterion.
Table 22. Comparison of Costs and Other Criteria of Representative Chemical
Inactivation Technologies
Criteria
Chlorine/
Sodium
hypochlorite
(CI2/NaOCI)
Chlorine
Dioxide
(CI02)
Liquid
Ozone (03)
Sodium
Bromide
(NaBr)
Peracetic
Acid
(CH3CO3H)
Occupational Safety
Requirements
Moderate -
High
High
Moderate -
High
Moderate
High
Ease of Operation
Simple
Simple -
Moderate
Moderate -
Complex
Simple -
Moderate
Simple -
Moderate
Generation Equipment
Required
No
Yes
Yes
No
No
Persistent Residuals
Yes
Yes
No
Yes
No
Power Requirements
Low
Low
High
Low
Low
Present Worth Cost
Low
Low -
Moderate
High
Moderate
Low
The occupational safety requirements reflect the quantity and complexity of safety barriers required to maintain operator safety.
The persistent residuals are a measure of the chemical inactivation agent that remains as a residual after the inactivation process is
complete. This parameter also includes chemical by-products.
Present worth cost includes capital and annual operational and maintenance costs.
2.3.6 Regulatory Issues
In the U.S., many of these chemicals are regulated by EPA and the U.S. Food and Drug
Administration (FDA). Chemical inactivation agents intended for use on surfaces are regulated
by the Antimicrobials Division, Office of Pesticide Programs, EPA, under the authority of the
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1947, as amended in 1996
(FDA, 2000). Under FIFRA, any substance or mixture of substances intended to prevent,
destroy, repel, or mitigate any pest, including microorganisms but excluding those in or on living
man or animals, must be registered before sale or distribution. The U.S. EPA requires
manufacturers to test formulations by using accepted methods for biocidal activity, stability, and
toxicity to animals and humans. Manufacturers submit these data to U.S. EPA with proposed
labeling. If EPA concludes a product may be used without causing unreasonable adverse
effects, the product and its labeling are given an EPA registration number, and the manufacturer
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
may then sell and distribute the product in the U.S. FIFRA requires users of products to follow
the labeling directions on each product explicitly. APHIS recommends that the selection of the
chemicals and inactivation methodology should be made from available U.S. EPA registered
products (USDA, 2014). The chemical products will either have been registered under FIFRA
Section 3 (i.e., a regular label) or exempted under FIFRA Section 18 (i.e., emergency use label).
In some situations (such as highly contagious foreign animal diseases), a particular pathogen
may not be listed on the product label of an U.S. EPA-registered product. In these cases,
Section 18 of FIFRA authorizes U.S. EPA to grant exemptions to Federal Agencies or States to
use unregistered chemicals for a limited time, if U.S. EPA determines that emergency conditions
exist. Use is allowed only for designated personnel and as described in the exemption. Under
regular conditions, the chemicals should be used according to their approved labels following
the indicated dilution, use sites, application method, contact time, precautionary statements, and
other appropriate information, against the pathogens specified on the label. Not following the
specified dilution, contact time, method of application, or any other condition of use is
considered misuse of the product. A registered chemical inactivation agent may also be used
according to label directions against pathogens not listed on the label provided that this use is
not in conflict with State or local regulations. The non-label-listed pathogens should be equally
or more sensitive to inactivation by the chemical than the hardiest pathogen listed on the
registered label.
Regulations, requirements and protocols for chemical inactivation should be consistent with the
State and federal laws. They must have a sound technical basis, and should be clear and
easily explained. Individuals responsible for the application, certification or planning of activities
and regulations related to chemical inactivation must periodically evaluate the scientific,
technical and pragmatic logic of programs (Kahrs, 1995). Effective inactivation of infectious
carcasses requires knowledge, a clear plan of action, regulatory discipline, documentation and
evaluation. Regulatory surveillance may be required to ensure the following key areas: a)
maximum efficiency in product utilization; b) application of all possible safety precautions for
personnel, equipment and the environment; c) effective, carefully-engineered handling and
processing steps; d) conscientious application of chemicals to the appropriate surfaces. At the
policy level, inactivation procedures and regulations must be reviewed constantly and evaluated
in the light of rapidly advancing technology and changing public values with respect to human
safety, residue hazards and environmental awareness. Chemical additive users and their
supervisors must have clear goals for each procedure in each specific setting. The personnel
must understand the effective spectrum of the inactivation being used, its limitations, and the
potential hazards to users, bystanders, equipment and the environment arising from use of the
product. Hazards to personnel can arise from chemical toxicity or infections acquired from the
carcasses being handled and processed. Economic factors must be secondary to safety
considerations.
2.3.7 Personnel Safety
Before any pretreatment work is initiated, all members of the team should have a complete
orientation covering the nature of the disease and the various hazards that may be encountered
while serving during an incident. A complete understanding of the specific safety precautions
should be obtained before entering the premises. This understanding is particularly important if
a zoonotic disease is involved. Most chemical inactivation agents can cause irritation to eyes,
skin, and/or the respiratory tract; some may cause burns or other injury. The safety of all
personnel must be paramount when handling, mixing, and applying chemical products. It is
essential that personnel be trained on proper storage, mixing and application procedures, and
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
hazards of the products they will be using. PPE such as hand, face, and eye protection should
be worn during the mixing or application of chemicals. All chemical compounds have an SDS
that includes the environmental hazards (risks, safety, and effect on the environment), stability
of the compound, hazards and personal protection needed, as well as first aid information.
Personnel engaged in cleaning and disinfection operations should wear at a minimum coveralls,
boots and gloves. Face protection (e.g., goggles, mask, face shield) should be worn based on
the product or application method (e.g., misting) used and when mixing chemical solutions.
Masks should also be worn in situations involving significant amounts of dust generation or
zoonotic disease potential. Chemical-resistant suits including both pants and jackets with hoods
or respirators may be necessary for some situations (such as formaldehyde or acidic chemical
application).
2.3.8 Community Acceptance
The treatment and processing of infectious animal carcasses without releasing pathogens to the
environment and treating the whole or processed carcass material to inactivate pathogens or
stabilize the carcass material in a manner suitable for appropriate carcass management are
essential during a large outbreak. However, the perception of creation and publicized
mismanagement of hazardous wastes necessitates the orchestration of a public involvement
process to minimize adverse reactions. Environmental acceptability would be the main criterion
for selection of a pretreatment facility and treatment processes. The government would reserve
the overall right of final selection. Given the potentially volatile nature of the siting issue, the
main thrust should be to develop an environmentally sound procedure and to link it to public
involvement. Social issues can create far more problems than technical issues. Opposition
rises when the public perceives that the project does not solve a local problem. A strong
commitment to fostering good community relations on the part of the sponsoring agency, a
strong commitment to access to information, the cooperative involvement of government and
citizen groups, and training and local job growth can bring significant success. The credibility of
the agency is a critical factor in acceptance by the public. If the public perceives that there is
need for the protection of human health and environment from infectious carcass materials, then
the benefits far outweigh the costs of the facility. The importance of the media cannot be
overemphasized.
2.3.8.1 Media/Public Information
The communication of carcass inactivation and treatment plays an important and vital role in the
successful emergency response program. The technique to communicate a volatile issue that
involves pathogens, chemicals, and hazardous waste requires a well-defined plan with clearly
stated objectives. The key factors surrounding the treatment facility can be communicated
through: a) provision of communication services to key government officials; b) provision of
communication services to public participation personnel with public groups; c) liaison with the
media; and d) ensuring that the key personnel are accessible to the media.
2.4 Combined Physical and Chemical Inactivation
The application of a combination of inactivation techniques can have a synergistic effect on the
inhibition or inactivation of the prevalence and the numbers of microbial pathogens in the
carcasses (Huffman, 2002). The combination of inactivation techniques can be implemented by
simultaneous application (such as acid solutions) or the sequential application of treatments
(such as hot water treatments and organic acids). Two or more technologies at suboptimal
levels are more effective than one at optimal level (Hugas and Tsigarida, 2008). For example,
reduction of numbers of Enterobacteriaceae, total coliforms, thermotolerant coliforms, and E.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
coli obtained by steam vacuuming were significantly lower than those obtained by a combination
of steam vacuuming with any other sanitizing treatment, e.g. treatments of hot water (95 °C) or
2% lactic acid (Castillo et al., 1999). The agents causing TSEs vary in their resistance to
inactivation by physical agents. In general, TSE agents are much more resistant than
conventional infectious agents such as bacteria and viruses, to heat, ultraviolet radiation,
ionizing radiation and microwave irradiation. The resistance of TSE agents to heat varies with
the material in which the agent is present (e.g., tissue size and composition) and has been
shown to increase if the agent has been fixed (e.g., by ethanol or formalin) or if material
containing the agent becomes attached to glass or metal. During the early stages of
procedures such as autoclaving designed to inactivate pathogens, a proportion of the agent
may become heat fixed onto surfaces, following which this fraction of the original quantity of the
agent becomes resistant to further heating. Incineration at high temperatures (e.g., 1,000 °C) is
effective in removing infectivity, although trace infectivity could be detected following
incineration at 600 °C followed by rehydration of the resultant ash. TSE agents also are
resistant to acids and alkalis. However, a combination of alkali plus heating, e.g., autoclaving at
120 °C for 30-90 minutes following or in the presence of concentrated alkali (1 M or 2 M sodium
hydroxide), has been reported to be effective for the inactivation of various scrapie strains
(Taylor, 2000).
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
3.0 Analysis of Pretreatment Technology Alternatives
Each carcass pretreatment technology
was evaluated against the nine criteria
that are based on the statutory
requirements of CERCLA, as amended
by the Superfund Amendments and
Reauthorization Act (SARA), Section
121; the National Contingency Plan
(NCP); and the guidance for conducting
remedial investigations and feasibility
studies under CERCLA (U.S. EPA,
1988). The first two criteria are
thresholds that must be satisfied for a
remedy to be eligible for selection; the
next five are balancing criteria used to
evaluate the comparative advantages
and disadvantages of the treatment
options; and the final two are modifying
criteria generally taken into account
after agency and public comments are
received on the FS and proposed plan.
These criteria to evaluate feasibility of
selected carcass pretreatment
technologies are summarized below
(see Figure 5).
Overall Protection of Human Health
and the Environment
How the risks are eliminated, reduced, or controlled
through treatment, engineering, or institutional controls.
Compliance with Applicable or Relevant and
Appropriate Requirements (ARARs)
Federal and state environmental statutes met
or grounds for waiver provided.
<}
4
£
Long-term Effectiveness
Maintain reliable protection of human health and
the environment over time, once cleanup goals are met.
Reduction of Toxicity, Mobility, or
Volume (TMV) through Treatment
Ability of a remedy to reduce the toxicity, mobility, and
volume of the hazardous contaminants present at the site.
Short-term Effectiveness
Protection of human health and the environment
during construction and implementation period.
Implementabillty
Technical and administrative feasibility of a remedy,
including the availability of materials and services
needed to carry It out.
Cost
Estimated capital, operation, and
maintenance costs of each alternative.
State Acceptance
State concurs with, opposes, or has
no comment on the preferred alternative.
Overall Protection of Human Health
and the Environment: This threshold
criterion assesses whether each
alternative, as a whole, protects human
health and the environment and
indicates how each hazardous
substance source is to be eliminated,
reduced, or controlled. The overall
assessment of protection draws on
evaluations conducted under other
evaluation criteria, especially long-term
effectiveness and permanence, short-term effectiveness, and compliance with ARARs.
$
Community Acceptance
Community concerns addressed;
community preferences considered
ft
Figure 5. Criteria Evaluated for Selected Carcass
Pretreatment Technologies
Compliance with Applicable or Relevant and Appropriate Requirements (ARARs): This
threshold criterion evaluates each alternative's compliance with ARARs, or if an ARAR waiver is
required, how the waiver is justified. ARARs consider location-specific, hazard-specific, and
action-specific concerns. The selected pretreatment alternatives evaluated and ranked based
on APHIS disease response protocols and environmental regulations.
Long-Term Effectiveness and Permanence: This balancing criterion evaluates the
effectiveness of each alternative in protecting human health and the environment after the
treatment action is complete. Factors considered include (1) magnitude of residual risk
remaining from untreated waste or treatment residuals at the completion of the pretreatment
72
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
action, and (2) adequacy and reliability of controls such as containment systems that are
necessary to manage treatment residuals and untreated waste.
Reduction in Toxicity, Mobility, or Volume through Treatment: This balancing criterion
addresses the statutory preference for selecting remedial actions that employ treatment options
that permanently and significantly reduce toxicity, mobility, or volume of hazardous substances
as their principal element. This preference is satisfied when treatment is used to reduce the
principal threats at a site through destruction of toxic contaminants, reduction of the total mass
of toxic contaminants, irreversible reduction on contaminant mobility, or reduction of total
volume of contaminated media.
Short-Term Effectiveness: This balancing criterion addresses the effectiveness of each
alternative in protecting human health and the environment during construction and
implementation of the remedial action. Factors considered include:
• Potential exposure of the community during implementation of an alternative
• Potential exposure of the workers during construction
• Potential effects to the environment
• Time required to meet the treatment and/or carcass management objective.
Implementability: This balancing criterion addresses the technical and administrative
feasibility of implementing an alternative and the availability of the required services and
materials during its implementation. Factors considered include:
• Ability to construct and operate the technology
• Availability and reliability of the technology
• Ease of undertaking additional remedial actions
• Administrative implementability
• Coordination activities with other agencies
• Monitoring considerations
• Availability of equipment and specialists.
Cost: This balancing criterion evaluates the present value of the capital and O&M cost for each
alternative. Capital and O&M cost estimates are order-of-magnitude-level estimates and have
an expected accuracy of minus 30 to plus 50 percent (U.S. EPA, 1988).
State Acceptance: This modifying criterion evaluates the technical and administrative issues
and concerns the regulatory agencies may have about each alternative. This criterion has not
been ranked as it was assessed under compliance with ARARs.
Community Acceptance: This modifying criterion evaluates the issues and concerns the
public may have about each alternative.
Based on the screening and evaluations (section 2), the following carcass pretreatment
technologies and process options were retained:
• No Pretreatment
• Size Reduction
• Size Reduction and Physical Inactivation
• Size Reduction and Chemical Inactivation
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Under the no pretreatment alternative, carcass would be disposed without implementing any
pretreatment or other mitigating actions to control exposure to hazardous material in the
environment. This response action would not be effective in reducing potential risks to human
health and environment. No cost is associated with this option because no pretreatment is
performed. The NCP requires that the no action response be included among the alternatives
evaluated in every feasibility study (Title 40 CFR Section 300.430[e][6]). The no action
alternative provides a baseline for comparison to the other pretreatment alternatives.
Table 23 provides the overall ranking of the pretreatment alternatives. The ranking of nine
criteria was performed using 1 to 5 scale (1 = very negative, 2 = negative, 3 = neutral, 4 =
positive, and 5 = very positive). Colors have been assigned to cells as visual aids (¦ = very
negative, 8SS = negative, = neutral, = positive, and ¦ = very positive). The total scores of
various alternatives for six carcass management options (EPA, 2016) show the relative ranking
of the pretreatments. The size reduction alternative with and without physical inactivation
ranked higher for most of the carcass management options. Citric acid and the oxidizing agent
(Virkon-S™) are considered more favorable than bleach due to the hazardous decomposition,
incompatibility to materials, corrosivity, toxicity, and other potential health effects of hypochlorite.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
Table 23. Comparison of Pretreatment Technologies and Overall Ranking against Various Carcass Management Options
No
Pretreatment
Size
Reduction (1)
Size Reduction +
Physical Inactivation
Criterion
Size Reduction + Chemica nactivation
Bleach
(Hypochlorite)
Oxidizing Agent
(Virkon-S)
Chemical Inactivation Agent
Citric)
Overall protection of human
health and the environment
Compliance with ARARs
Long-Term Effectiveness
and Permanence
Reduction of Toxicity,
Mobility, and volume
through Treatment
Short Term Effectiveness
Implementability
Rendering
Buria
Landfill
Composting
ncineration
i
Burning
State Acceptance
Commu n ity Acce ptance
TOTAL SCORE
Rendering
27
28
34
33
25
28
Burial
28
26
32
33
25
28
Landfill
26
27
34
34
26
29
Composting
27
28
33
34
26
29
Incineration
25
28
32
34
25
28
Burning
25
28
32
34
25
28
Legend
1 = very negative [¦); 2= negative (^); 3 = neutral (¦); 4- = positive 5 = very positive (¦)
Notes: (1) Assumes aerosols and liquids that are generated during size reduction are contained.
(2) ARARs refers to APHIS disease response protocols and environmental regulations.
(3) Assumes the physical inactivation by heating to be performed at less than 212 °F (100 °C); and the product market will be limited.
(4) Similar to ARARs; thus, not considered twice.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
4.0 Summary
The highly pathogenic avian influenza (HPAI) outbreak in the U.S. in 2015 was the worst poultry
disease outbreak in the country's history. According to the USDA (2015a), the disease claimed
more than 49 million birds on 211 commercial farms or premises. Approximately 7.5 percent
and 10 percent of the U.S. turkey and egg layer inventories, respectively, were removed from
production due to the outbreak. The availability of carcass management options was limited
due to concerns about transporting and disposing of/treating infected material. Should a major
disease outbreak occur whether inadvertent or intentional, it is crucial to have an effective
infected carcass treatment and carcass management strategy. From an economic sense, such
strategies would be designed to minimize the costs arising from livestock losses, economic
impacts, government costs, public health hazards, and environmental damages. Carcasses
resulting from highly infectious diseases such as HPAI may potentially be disposed of more
easily if the materials are pretreated at the farm to inactivate pathogens using an appropriate
pretreatment, under the direction of well-trained professionals with regulated supervision.
Feasible pretreatment alternatives evaluated in this study applied prior to the routine and
catastrophic management of infectious carcasses include size reduction alone or with physical
or chemical inactivation. Size reduction combined with citric acid had the highest overall
ranking of the evaluated alternatives.
Direct comparison between pretreatments in this study was complicated by numerous variables
such as mode of application, the concentration used, the application of temperature, the
exposure time, the point of application during processing, or contamination level of carcasses.
If more than one inactivation treatment should be applied to carcasses, the combined
microbiological reduction effect might be greater than the effect of one treatment alone.
Methods, strategies, and practical applications presented in this report describe acceptable
means for treatment of carcasses prior to disposal. Each treatment has its advantages and
disadvantages as costs and benefits. The actual decision on which treatment or combination of
treatments are suitable should be based on individual circumstances and the restrictions that
apply. The overall objective of ensuring a high level of protection for the environment as a
whole may involve making trade-off judgments between different types of environmental impact,
and these judgments can be influenced by local considerations. The obligation to ensure a high
level of environmental protection including the minimization of long-distance or trans-boundary
pollution implies that the most appropriate techniques cannot be set on the basis of purely local
considerations.
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Feasibility of Selected Infectious Carcass Pretreatment Technologies
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