Standard Operating Procedure for Monitoring of Laboratories for Airborne Contaminants SOP Number: QC-02-05 Date Revised: 04-15-14


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US Environmental Protection Agency
Office of Pesticide Programs
Office of Pesticide Programs
Mic ro bio lo gy La bo ra to ry
Environmental Science Center, Ft. Meade, MD
Standard Operating Procedure for
Monitoring of Laboratories for Airborne Contaminants
SOP Number: QC-02-05
Date Revised: 04-15-14

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SOP No. QC-02-05
Date Revised 04-15 -14
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SOP Number
QC-02-05
Title
Monitoring of Laboratories for Airborne Contaminants
Scope
This SOP describes a method for determining the occurrence
(number and type) of airborne microorganisms in the laboratory.
Application
This procedure was designed based on references mentioned in
section 15. Additional attributes have been added to detect airborne
contamination in specific environments.


Approval Date
SOP Developer:

Print Name:
SOP Reviewer

Print Name:
Quality Assurance Unit

Print Name:
Branch Chief

Print Name:


Date SOP issued:

Controlled copy
number:

Date SOP withdrawn:

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SOP No. QC-02-05
Date Revised 04-15 -14
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TABLE OF CONTENTS
Contents	Page Number
1.
DEFINITIONS
3
2.
HEALTH AND SAFETY
3
3.
PERSONNEL QUALIFICATIONS AND TRAINING
3
4.
INSTRUMENT CALIBRATION
3
5.
SAMPLE HANDLING AND STORAGE
3
6.
QUALITY CONTROL
3
7.
INTERFERENCES
3
8. NON- C ONF ORMIN G DATA
3
9.
DATA MANAGEMENT
3
10.
CAUTIONS
3
11.
SPECIAL APPARATUS AND MATERIALS
3
12.
PROCEDURE AND ANALYSIS
3
13.
DATA ANALYSIS/CALCULATIONS
5
14.
FORMS AND DATA SHEETS
6
15.
REFERENCES
6

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SOP No. QC-02-05
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1. Definitions
Abbreviations/definitions are provided in the text.
2. Health and Safety
Follow procedures specified in SOP MB-01, Laboratory Biosafety. The
Study Director and/or lead analyst should consult the Material Safety Data
Sheet for specific hazards associated with products.
3. Personnel
Qualifications and
Training
Refer to SOP ADM-04, OPP Microbiology Laboratory Training.
4. Instrument
Calibration
Refer to QC-22: VITEK 2 Compact.
5. Sample Handling
and Storage
Not Applicable
6. Quality Control
For quality control purposes, the required information is documented on the
appropriate form(s) (see section 14).
7. Interferences
1.	Building construction, power outages and equipment maintenance may
cause transient aberrant counts. These events should be considered
while interpreting results of the air testing and efficacy tests conducted
during that time. Note these events in the comments section of the Air
Monitoring Record Form (see section 14).
2.	Media must pass sterility and performance assessment in advance of
use.
8. Non-conforming
Data
1. Management of non-conforming data will be consistent with SOP
ADM-07, Non-Conformance Reports.
9. Data Management
1. Data will be archived consistent with SOP ADM-03, Records and
Archives.
10. Cautions
1. If any unusual air handling events take place (e.g., significant
laboratory air flow changes, construction within the facility), air
monitoring may be conducted at any time to verify the quality of the
lab's air according to procedures described in section 12.
11. Special Apparatus
and Materials
1. Trypticase Soy Agar (TSA) plates or TSA with 5% sheep's blood.
12. Procedure and
Analysis
1.	The assay is conducted to investigate possible contamination sources.
2.	Conduct the test only on the affected laboratory if possible.
3.	In this method, general growth media are exposed to the environment
to monitor the occurrence of airborne microorganisms (e.g., bacteria,
mold and yeast). This is a passive air sampling method. The test can
be performed on an as needed basis or at least once a year for all

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SOP No. QC-02-05
Date Revised 04-15 -14
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laboratories.
4.	Petri plates containing TSA and/or Sabouraud Dextrose Agar (SDA)
are exposed to the environment for a specific period of time at various
sites in a laboratory (sample locations include bench tops, incubators
and biosafety cabinets etc).
5.	The presence of contamination may be due to air flow changes, facility
construction amongst others.
12.1 Conducting the
Assay
a.	Locations to be assayed are identified based on where the
contaminants) were observed within a test system, assay or routine
laboratory work, or if unusual air handling takes place.
b.	Determine the laboratory sites to be evaluated prior to commencing the
assay.
c.	Record the sites within the laboratory that will be evaluated on the
corresponding form (see section 14).
d.	Determine the contact time for plates to be exposed to the environment.
The time frame of exposure should be between 15-60 minutes. All
exposed plates should be left uncovered for the same amount of time.
e.	Label plates in accordance with their locations where they are placed in
a laboratory (room #, specific sites in a lab, etc.)
f Place the plates at desired locations and remove the covers sequentially
at 15-30 second intervals.
g.	Expose the plates for the pre-determined amount of time (15-60
minutes).
h.	Replace the covers after exposure time is completed, in sequential
order. Record exposure time on the appropriate form (see section 14).
i.	Incubate the plates at 36±1°C (for TSA) or at 24±1°C (for SDA) for 2 to
7 days. Wrap plates in parafilm to prevent dehydration during extended
period of incubation (> 48 hours). Plates may be observed daily for
growth.
j. Count colonies and record the number of colonies per square foot (up to
300 CFU per plate), counts > 300 CFU are recorded as too numerous to
count or TNTC). Refer to section 12.2 for interpretation of results.
12.2 Interpretation of
Results and
Decontamination
a.	The number of organisms which settle in 15 minutes of exposure on a
petri dish is equivalent to that for 1 sq. foot.
b.	If results indicate contamination that exceeds 15 colonies/plate/15
minute (see section 15) or if the laboratory base line established on past

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SOP No. QC-02-05
Date Revised 04-15 -14
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historical data appears higher than normal, then the source of
contamination is investigated.
c.	Perform general laboratory cleaning using an antimicrobial product, if
necessary.
d.	Following the cleaning process, repeat the air monitoring procedure.
Operation in a laboratory may be suspended until the problem is
resolved.
e.	If one of the exposed plates, corresponds to a location inside a BSC and
exhibits an unacceptable level of contamination (15 colonies/plate/15
minute or if laboratory base line established on past historical data
appears higher than normal), then the BSC is not used.
i.	Inform the ESC Facility Manager.
ii.	Decontaminate the BSC if necessary, using an EPA registered
disinfectant (the disinfectant is used following the label instructions
for the determined amount of contact time).
iii.	Repeat the air monitoring test for the affected BSC.
iv.	Do not use the BSC until the air monitoring indicates acceptable
level of microbial counts.
12.3 Identification
and
Confirmation of
Contaminants
a.	Conduct a Gram stain on contaminants.
b.	Further presumptive identification may be conducted by plating onto
general and/or selective media, if necessary.
c.	Conduct VITEK identification if absolutely necessary.
Note: It may be necessary to use a specific growth medium and incubation
conditions if one is attempting to identify the presence of a more fastidious
microbe.
13. Data Analysis/
Calculations
1.	Determine the number of CFUs per 15 x 100 mm plate per 15 minute
period (or multiply with the factor if the exposure time is more than 15
minutes, e. g., the number of CFUs be multiplied with 2 if the exposure
time is 30 minutes (see section 15).
Final number of contaminant/plate: (x CFU) X (y) = z
Where x = number of CFU/plate, y = exposure time multiplying factor and
z = final number of contaminants per plate.
2.	For example: if a plate has 10 CFU and was exposed for 30 minutes
then, 10 CFU x 2 = 20 CFU. In this case y = 2 since the exposure time
was 30 minutes; y is always 1 if the exposure time is 15 minutes, as
described in 13.1. In conclusion, this plate indicates a higher than

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normal presence of contamination.
14. Forms and Data
Sheets
1. Test Sheets. Test sheets are stored separately from the SOP under the
following file names:
Air Monitoring Record Form QC-02-05 Fl.docx
15. References
1.	Bordner, R.H., Winter, J.A., & Scarpino, P.V., eds. 1978.
Microbiological Methods for Monitoring the Environment, Water, and
Wastes. EPA 600/8-78-017, Part IV Quality Assurance, U.S.
Environmental Protection Agency, Cincinnati, Ohio.
2.	Eaton, A.D., Clesceri, L.S., Rice E. W. eds. 2005. Standard Methods
for the Examination of Water and Wastewater, (Page 9-4), 21st Edition.
American Public Health Association, American Water Works
Association, Water Environment Federation

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