In the past decade, there has been a nearly three-fold increase in demand for pathogen screening by North American food companies alone, leading to an advent of new technologies that have revolutionized the sensitivity and accuracy of pathogen tests. These newer comprehensive methods are more sensitive, more accurate, more cost-effective, and faster (1-2 days instead of 3-5 days or weeks) than previous traditional methods. Typically, most pathogen and environmental testing procedures outlined above follow a series of steps: 

Take a small sample of the food product or equipment sample. The sampling procedure and processing of samples varies depending on whether it comes from a dairy, meat, or produce plant or a packaged food facility.

The food sample is then transported to a laboratory and added to a ‘stomacher bag’, which is essentially a sterile plastic bag containing an enrichment medium. The bag containing the sample (in media) is then ‘massaged’ by 2 paddles of a stomacher instrument to homogenize the sample and ‘enriched’ to increase the pathogen load. This enrichment step is important to let the contaminating pathogens reach a threshold appropriate for detection. This pre-enrichment step can take from 12-24 hours and represents a fundamental step in the testing process. Similarly, environmental sampling may also require taking a swab of the food plant’s processing equipment and doing a pre-enrichment for amplification of potential bacterial load.

The prepared sample can now be tested according to four commonly employed testing procedures that include DNA-based PCR methods, Immunoassays (ELISA), Real Time Hygiene Monitoring Systems, or Traditional Microplating. Depending on the technology, actual detection can range anywhere from 10 minutes (fast, rapidly automated) to up to 48 hours (traditional micro-plating techniques). Note that these timelines are POST-enrichment, which itself ranges from 12 to 24 hours.