The role of effective microbial testing becomes much more critical to the food processing industry, especially with recent foodborne outbreaks, confirming the need to detect and identify the often nonconventional sources of contamination as early as possible. Globally, the U.S. Food Safety Modernization Act as well as Global Food Safety Initiative schemes such as Safe Quality Food, British Retail Consortium, etc. also require food manufactures to fully ensure the safety of food supplies throughout ingredient acquisition, handling, processing, packaging, storage and distribution.
To date, instead of conducting in-house microbial screening, the majority of small-to-medium-size food companies rely solely on sending samples out to commercial labs, which often require a 4–7-day turnaround time. Not only does such a holding time delay the release of the products, but it also eliminates the opportunity to catch where and how the contamination might have occurred, rendering the products susceptible to recurring problems. Therefore, there is a dire need for the food processing industry to establish on-site microbial screening capacity using tools that are reliable, robust, easy to operate and cost-effective.
On-site screening capacity using protocols approval by professional standard-setting organizations carries multiple advantages: (1) more products could be screened in-house; (2) various ingredients, premixes or semi-finished products could be tested for their microbial load before they are employed or processed further; (3) verification of cleaning and sanitation procedures could be conducted more effectively with in-house microbial screening capacity; and (4) samples that tested positive using the in-house screening tool can be sent out to full-blown microbial laboratories for confirmation or even to conduct challenge studies.
Recent advancements in PCR-based detection methods eliminate the concern of bringing pathogenic microbial organisms into processing environment. By using a segment of signature DNA representing the target pathogen such as Escherichia coli O157, Salmonella or Listeria, PCR-based methods could identify the existence of the microorganisms without employing the pathogens in the lab, thus eliminating worries of maintaining active culture of pathogens adjacent to food processing areas. In addition, accelerated PCR methods approved by AOAC International have been demonstrated to reduce the detection time to 8–24 hours in comparison with typically 2–3 days when using conventional agar plate culture.
It is the author’s intent to stimulate more research and discussion in the area of automated microbial screening of foodborne pathogens in hope to provide accurate, cost-effective and user-friendly tools that could be readily implemented on-site at food processing facilities.
Y. Martin Lo, Ph.D. is CEO & president of Biointellipro LLC, a consulting firm for the complex and increasingly challenging food and agriculture system.