USDA Food Safety llnd Inspection Service 

.iiiiiii US.cmi.RTMEl-ll' ClF.\GROJ.n.RE 

Inappropriate Sized Sampling Devices 

Not using a neutralizing broth. 

1

2

7/27/2022

• A 12”x12” area should be sampled, when possible, for FCS and NFCS. If the surface area is smaller

than 12”x12”, then the entire surface should be sampled. 

• Smaller sampling devices are not recommended for sampling large areas because they may become

saturated. 

12 square inches

12’’

Smaller devices may be

used for small spaces.

4 x 4

2

Establishments should utilize a neutralizing broth in FCS and NFCS

sampling devices. If not, it could result in false negative results. 

USDA FSIS utilizes Dey Engley (DE) Broth because;

• It neutralizes a broad spectrum of antimicrobials, disinfectants,

and sanitizers

• DE broth had the greatest efficacy at the time it was adopted.

Other neutralizing broths:

• Letheen Broth

• Neutralizing Buffer

• HiCap Neutralizing Buffer (newest) 3

3

1
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Improper storage, shipment, or analyses of samples. 

Sampled Portion vs. Test Portion 

Sample Compositing 

IUIIC'llUI 

NNnlfl£Ill 

4

5

7/27/2022

FSIS Guidance;

Samples should be stored and shipped under refrigeration.

• No freezing or excessive heat.

• Refrigeration temps are typically about 2 – 8 C, or 33 – 45 F. 

More FSIS Guidance;

• For external labs, limit to 2-3 days from collection to start of analyses.

• For in house lab, initiate testing immediately after collection. 

• If not, must support alternative timeframe won’t compromise

sensitivity.

4

• The entire swab or sampling device should be included in the

enrichment step.

• Microbiological contamination is non-homogonous.

• NFCS are typically the original source of contamination of FCS

and product.

• A negative FCS swab does not indicate that FCS is always

negative.

• A single negative product sample is not proof the entire lot is

negative.

5

One sampling device should be utilized per surface location. 

If not;

• Potential saturation of sampling device. 

• Potential cross contamination across various surface locations.

FSIS recommends that no more than 5 samples be composited;

• Supported by the Lm compliance guide.

• Best if composited by laboratory staff.

• Will lose location specific results. 

• Must take corrective actions as if all locations are positive.

6

6

2
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analytical Methods 

:5'\:J 

AOAC 

INTl illN,llif'IQf\lAL 

afnor CERTIFICATION 

Analytical Methods 

Analytical Methods 

International 

Organizal ion for 

Standardization 

7

8

7/27/2022

See Foodborne Pathogen Test Kits Validated by Independent Organizations

(usda.gov).

Establishments and laboratories should choose test kits that are:

1. Validated for testing relevant foods by a:

a) Recognized independent body (i.e., AOAC, AFNOR, MicroVal, NordVal),

b) U.S. regulatory body (i.e., FSIS MLG or FDA BAM), or

c) International Organization for Standardization (ISO) process.

7

2) In addition, the validated method should be:

a) Fit for the intended purpose and application, and

b) Performed per the conditions of the validated protocol

by a laboratory that assures the quality of the analytical results.

FSIS considers a laboratory to be one that assures the quality of its

analytical results if it meets the guidance in FSIS’ Establishment Guidance

for the Selection of a Commercial or Private Microbiological Testing

Laboratory (usda.gov).

8

Is the lab accredited to ISO 17025 or following FSIS guidance?

• Qualifications of personnel.

• Sample receipt and handling.

• Quality Assurance Management System.

• Method Selection and Implementation.

• Reporting Results.

Is the lab performing the method as it was validated.

• Look for the matrices that were used in the validation

• Also, look at sample size, enrichment broth(s), times, temperatures,

etc.

Submit questions or concerns to askFSIS.

9

9

3
 

 

 

 

 

 

 

 

 

 

 

 

 

Establishment Implementation Issues 

Implementation Issues 

USDA Food Safety llod Inspection Service 

-- US.~OF.\GftO..l.n.1!£ 

10

11

7/27/2022

• Not listing or testing all FCS sites.

• Should sample the riskiest locations the most often.

• Not testing at the frequency stated.

• Not applying an antimicrobial agent or process AMAP appropriately.

• The establishment signed pre-shipment review prior receiving

sample results.

10

Testing for Lm, but their program states they will test for L. species. 

• A product that passes over an FCS which tests positive for Lm is

considered adulterated.

• A finding of Listeria spp. on an FCS indicates conditions where Lm

may be present, but the product is not considered adulterated. 

Establishments must take corrective actions for all Listeria spp. or

Lm positives so that product does not become adulterated.

The establishment is not supporting Lm or Sal is not a hazard RLTO

for RTE ingredients introduced post-lethality, i.e., spices, sauces, etc.

11

12

4
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EIAO Sampling, Shipping, or Packaging Issues. 

EIAO Sampling, Shipping, or Packaging Issues. 

Issues with Forms, Seals, Bar-Coded Labels. 

13

14

7/27/2022

Ensure you have adequate sampling supplies upon receipt.

• Once you’ve arrived at the establishment, it’s too late!

Frozen gel packs should be removed from the freezer and

placed into shipping containers on the day of shipment.

• If packed shipping containers are stored overnight, replace the

frozen gel packs on the day of shipment.

13

• Including samples from more than one line or lot within one unit

of samples.

• Each unit should be associated with only one line, one production

lot, and one 430 Alternative.

• If not, leads confusion when positives are found.

• Which production lots are implicated by a positive sample?

14

• There must be a corresponding form for all samples within each

shipping container.

• Each form must be signed.

• Each shipping container should be sealed to ensure sample

integrity, i.e., as illustrated in Direct8ive 7335.1.

15

15

5
 

 

 

 

 

 

 

 

 

DE Broth and Pre-hydrated Sponges 

16

17

7/27/2022

• DE broth can be held at typical room temperatures for long

periods of time.

• Printed shelf life is dependent on refrigeration.

• The higher the temperature, the faster DE broth degrades.

• Should be refrigerated for long term storage.

• Must not be frozen or temperature abused. 

16

Contact info

(if you would not like to include this

info, feel free to delete this text box)

fsis.usda.gov

6