FOOD PATHOGEN TESTING

Targeted Detection for Products, Ingredients, AND Food-Safety Programs

Foodborne pathogens may be present without causing visible changes in a product.

Biotrax provides third-party food pathogen testing for raw materials, ingredients, in-process samples, and finished food and beverage products. Our capabilities include targeted detection of Salmonella, Listeria monocytogenes, Listeria species, E. coli O157:H7, and Shiga toxin-producing E. coli, or STEC.

Pathogen testing may support product-release programs, supplier verification, customer specifications, HACCP and preventive-control verification, investigations, and other food-safety activities.

Not sure which organism, sample portion, or method applies? Tell us about your product and testing objective. Our team can help clarify the available options and what is needed before submission.

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When Food Pathogen Testing May be Needed

Food manufacturers and quality teams may request pathogen testing to:

Evaluate raw materials or incoming ingredients
Support finished-product release decisions
Meet customer or supplier requirements
Verify an established food-safety program
Investigate a complaint, deviation, or unexpected concern
Compare affected and unaffected product lots
Follow up on an environmental-monitoring finding
Confirm whether a specific pathogen was detected in the tested portion

The appropriate pathogen, method, analytical portion, and sampling plan depend on the product, process, identified hazard, and intended use of the results.

ASK US ABOUT YOUR PRODUCT

FROM SAMPLE TO PATHOGEN RESULT

Most food pathogen testing is performed as a presence-or-absence analysis. Rather than estimating how many organisms are present, the test determines whether the targeted pathogen was detected in the portion analyzed.

1. Sample Preparation and Enrichment

A defined portion of the sample is combined with an enrichment broth and incubated under method-specific conditions.

Enrichment gives low levels of the target organism an opportunity to multiply to a detectable level while helping recover cells that may have been stressed during processing or storage.

2. Rapid Pathogen Screening

Applicable samples are screened using bioMérieux VIDAS technology or a PCR-based method, depending on the target and testing program.

VIDAS is an automated immunoassay platform used to detect common foodborne pathogens. PCR testing detects selected genetic targets associated with the organism being screened.

3. Confirmation When Required

A negative screen completes the analysis when all method acceptance criteria are met.

A presumptive-positive screen is carried forward for confirmatory work according to the applicable laboratory method.

WHAT HAPPENS AFTER A PRESUMPTIVE POSITIVE?

A presumptive-positive screening result is not automatically treated as a final confirmed positive.

At Biotrax, presumptive-positive samples undergo additional cultural confirmation. This may include streaking the enriched sample onto appropriate selective or differential agar, incubating the plates, evaluating characteristic colony growth, and performing further identification steps required by the method.

For example, a presumptive pathogenic E. coli result may be plated onto an appropriate MacConkey-based selective or differential medium and incubated so characteristic colonies can be evaluated before further confirmation.

The exact agar, incubation conditions, and identification steps vary by organism, product matrix, and method. Salmonella, Listeria, and pathogenic E. coli each require organism-specific confirmation procedures.

Confirmatory culture extends the final turnaround time, but it helps distinguish an initial presumptive screen from a confirmed laboratory finding. FDA guidance similarly treats rapid-method positives as presumptive and requires confirmation using established cultural procedures.

Presumptive positive does not mean confirmed positive.

A rapid screen identifies a sample that requires further evaluation. The final result is issued after the applicable confirmation process is completed.

FOOD PATHOGEN TESTING CAPABILITIES PATHOGENS WE TEST FOR

SALMONELLA SPECIES

Salmonella is a group of foodborne bacteria associated with a wide range of ingredients and finished products.

Why test for it:
Testing may support supplier verification, raw-material programs, finished-product release, customer specifications, food-safety verification, or an investigation involving a suspected hazard.

Available analytical portions:
25-gram and 375-gram options are available depending on the product, specification, sampling plan, and program requirements.

LISTERIA SPECIES

Listeria species testing detects members of the broader Listeria genus rather than only L. monocytogenes.

Why test for it:
The presence of any Listeria species can provide useful information about hygiene conditions or environments that may also support L. monocytogenes. It may be requested as part of a broader monitoring, verification, or investigation program.

Available analytical portions:
25-gram and 125-gram options are available where appropriate.

Important Distinction:

A Listeria species result is not the same as a confirmed Listeria monocytogenes result. The selected analysis should match the organism the client needs to evaluate.

LISTERIA MONOCYTOGENES

Listeria monocytogenes is the disease-causing species associated with listeriosis. It is an important concern for ready-to-eat foods because it can survive and grow under refrigerated conditions.

Why test for it:
Testing may support finished-product safety verification, hold-and-release programs, investigations, customer requirements, and follow-up activities when the organism is identified as a relevant hazard.

Available analytical portions:
25-gram and 125-gram options are available based on the testing plan or specification.

E. COLI (including O157:H7)

E. coli O157:H7 is a pathogenic strain capable of producing Shiga toxin and causing serious foodborne illness.

Why test for it:
Testing may support verification for foods and ingredients where O157:H7 is a recognized hazard, including certain raw meat products, produce, ingredients, or other susceptible matrices.

Available analytical portions:
25-gram and 375-gram options are available depending on the specification, program, and sample type.

Important distinction:

This is different from generic E. coli enumeration, which is commonly used as a hygiene or process indicator.

LOOKING FOR GENERIC E. COLI COUNTS? VIEW MICROBIOLOGICAL TESTING

PCR STEC SCREENING

Shiga toxin-producing E. coli, or STEC, includes pathogenic strains that carry genetic markers associated with Shiga toxin production.

Why test for it:
PCR screening may be used when a product, ingredient, customer requirement, or risk-based program calls for evaluation beyond a general E. coli count.

Because STEC programs can differ in the genetic targets, serogroups, analytical portions, and confirmation requirements involved, the exact screening scope should be confirmed with Biotrax before samples are submitted.

SAMPLE PORTIONS

WHAT DO 25 G, 125 G, AND 375 G MEAN?

The analytical portion is the amount of sample that is prepared and tested for the target pathogen.

A larger analytical portion provides broader sample coverage, but it does not guarantee that the entire production lot is free from the organism. The appropriate portion may be determined by:

The product and identified hazard
A customer or supplier specification
Regulatory or industry guidance
The sampling plan
Lot size and production process
The intended use of the result
The laboratory method

Clients should not assume that a larger portion is automatically required or more appropriate. Our team can help confirm which option fits the testing request.

WHAT A PATHOGEN RESULT CAN — AND CANNOT — TELL YOU

A pathogen result applies to the tested analytical portion of the submitted sample.The usefulness of any result depends on proper sampling, representative sample selection, correct handling, the analytical portion, and alignment between the method and the client’s testing objective.

Not Detected

“Not detected” means the target organism was not found in the portion analyzed under the conditions of the method.

It does not prove that every unit or location within an entire production lot is free from the organism.

Presumptive Positive

A presumptive-positive screen indicates that the sample requires confirmatory evaluation. It is not yet a final confirmed result.

Confirmed Positive

A confirmed positive means the organism was supported by the applicable cultural and identification process.

WHERE PATHOGEN TESTING MAY FIT

PRODUCT AND PROGRAM APPLICATIONS

Raw Materials and Ingredients

Testing may help verify supplier requirements or evaluate ingredients associated with an identified pathogen risk.

In-Process and Finished Products

Pathogen testing may support process verification, product-release programs, customer specifications, and investigation of a production concern.

Retained or Investigative Samples

Affected products, retained samples, and comparison lots may be tested as part of a broader investigation.

Environmental Surfaces

Pathogen testing is also available for properly collected environmental swabs. Environmental pathogen swabs must be collected separately from quantitative indicator swabs.

EXPLORE ENVIRONMENTAL MONITORING

WHAT TO TELL US BEFORE SENDING A SAMPLE

When contacting Biotrax, tell us:

What the product or ingredient is
Whether the sample is raw, in process, or finished
Which pathogen you need to evaluate
Whether a customer or program specifies a method or analytical portion
Whether the test supports release, verification, or an investigation
The lot size and number of samples involved
When the sample was produced or collected
How it has been stored
Whether expedited screening or confirmation expectations apply

Pathogen testing commonly begins with a 25-gram analytical portion, but the total sample required may be greater depending on the target, portion size, number of analyses, and sampling plan. The guide recommends contacting Biotrax whenever the correct test, amount, packaging, or collection plan is uncertain.

NOT SURE WHICH FOOD PATHOGEN TEST TO REQUEST?

Tell us about your product, identified hazard, customer requirement, or concern.

Our team can help clarify the target organism, analytical portion, available method, sample requirements, and confirmation process.

LET'S DISCUSS YOUR TESTING NEEDS