Poultry and Meat Testing: Using Modern Pathogen Detection Technologies to Ensure Food Safety

Through the early 2000s, DNA-based methods commonly utilized polymerase chain reaction (PCR) to help amplify samples. PCR methods typically require multiple steps to process enriched food samples and amplify target DNA for detection of pathogens. More recently, new molecular tests have been developed with loop-mediated isothermal amplification (LAMP) technology to simplify and quicken the testing process.

Whereas PCR methods typically rely on two primers to copy and amplify a sample’s DNA and then read the strands, LAMP methods use between four and six primers, which, in addition to displacing the target DNA strand, also loop the ends of the strands together before the amplification process. This looping structure accelerates the reaction and increases the sensitivity of the test, allowing for a much, much larger accumulation of the target DNA.

LAMP technology also allows for minimal transfer steps instead of the multistep process used in PCR methods. A process with fewer steps allows labs to process more samples in less time, meaning reductions in cost, time, energy, and manpower.

The advent of molecular pathogen testing methods has also allowed technicians to become much more specific and accurate in their testing. For example, many processors are testing for specific serotypes of concern.

Pathogen Environmental Monitoring Programs

Pathogen testing of finished products, while crucial, should be viewed as only one part of a comprehensive pathogen prevention plan. The implementation of these technologies as part of a well thought-out, well-executed pathogen monitoring program is necessary for processors to prevent contamination with pathogens in ingredients and during processing operations.

Pathogen environmental monitoring (PEM) programs are often considered to represent a proactive approach to microbial food safety. These programs can identify challenges and pathogen sources within the manufacturing environment before they lead to contamination of finished food products.

PEM programs are typically used to validate and verify the suitability and effectiveness of food safety systems and to provide early indication of potential food safety hazards. The validation of sanitation procedures and other control strategies typically requires the use of multiple environmental monitoring approaches, including adenosine triphosphate (ATP) testing, to assess cleaning and total plate count (TPC) methods.

Often, use of these tests is supplemented with pathogen testing to identify specific harborage sites that allow for pathogen growth or survival. The process used to identify specific harborage sites or niches (e.g., as part of validation or similar type efforts) is often referred to as the “seek and destroy” technique. In addition to validation and verification, testing of environmental samples for pathogens is used to support root-cause analysis efforts and to verify that corrective actions taken are effective in addressing specific pathogen-related problems. These activities may be part of “for-cause” and “not-for-cause” investigations.

These tests are much less effective when done in isolation rather than as a comprehensive, custom PEM program tailored to a producer’s specific products and specific facility, which is designed to ensure that no likely harborage site is left untested. But, the specifics of how the plan is executed are just as important as the plan itself.

Small details, from the amount of pressure applied to a sponge to the specific locations tested (e.g., a floor crack vs. an adjacent uncracked floor section), can have a huge impact on whether pathogens are detected. Hence, it is important to design the sampling plan to avoid intentionally or unintentionally providing incentives for the sample collectors to not collect samples that would likely yield pathogen positives. For example, setting numeric targets or key performance indicators for the percentage of positive PEM samples may simply lead to sample collectors not collecting samples that will likely yield positives. The goal of a PEM program is to find and eliminate pathogen contamination in the processing environment, and this goal cannot be compromised.