Listeria Control Programs: A Journey Of Sampling To Prevention
By Sam Lewis, editor, Food Online
As the food industry shifts its focus from reacting to adverse events to preventing them, “An ounce of prevention is worth a pound of cure,” is becoming the new mantra. At the 13th Annual North American Summit On Food Safety, Nandini Natrajan, Ph.D., senior director of science operations at Keystone Foods, shared her insights on how both the FDA and USDA FSIS are approaching listeria control, as well as what those companies can do to mitigate their listeria risk and prevent listeria contamination-related recalls.
How Regulatory Agencies Are Approaching Listeria Control
One FDA regulation, the Foreign Supplier Verification Program (FSVP), is helping U.S. food companies control listeria. FSVP requires establishments producing FDA-regulated products for export to the U.S. to have safety programs that provide an equal level of protection of domestic facilities. That level of domestic food protection is provided by FSMA's Preventive Controls (PC) for Human Food Rule.
FSMA’s PC Rule requires ready-to-eat (RTE) products exposed to the environment after being cooked to include environmental sampling as part of a PC program. In the past, the FDA has not recommended testing Food Contact Surfaces (FCS) for listeria and facilities were not encouraged to look for listeria species in the environment.
Now, to minimize the potential for contamination of RTE foods, as well as FCSs, with Listeria Monocytogenes (LM), the FDA recommends establishing and using a sanitation program with written procedures. The agency also recommends creating a sanitation schedule for areas where RTE foods and FCSs are processed and/or exposed to LM risk. “We’re beginning to see a lot of overlap in LM programs between what’s been done under FSIS jurisdiction and what the FDA's going to start recommending,” says Natrajan.
Companies who fall under FSIS regulations need to have sanitation measures for controlling listeria. These can be incorporated into the establishment’s HACCP plan or in its Sanitation SOPs. “When these control procedures are part of sanitation SOPs, the establishment must have documentation supporting its hazard analysis that listeria contamination is not a reasonably-likely hazard,” says Natrajan.
FSIS-regulated facilities must have a verification program after RTE products are cooked. This verification program must include testing for LM or another listeria species. “As we all know, listeria comes from post-process contamination,” says Natrajan. “Once your product reaches its cooked temperature, no bacteria survives. If there is pathogenic contamination, it’s because it occurred post process and it cannot be assured pathogens aren’t harbored in the environment — heavy equipment such as forklifts, equipment control panels, and floors, ceilings, and walls.” This step essentially proves the effectiveness of the sanitation program. From there, these facilities must maintain sanitary conditions in post-cooking/processing environments to ensure contamination does not occur.
FSIS Compliance Guidelines
FSIS Listeria Compliance Guidelines are segmented into categories. The agency labels these “alternatives” — 1, 2, 2b, and 3. Companies falling under alternative 1 are low risk for listeria because they reduce or eliminate risk through a lethality step, often cooking, or an antimicrobial agent or process (AMAP) to suppress listeria growth in the product. Alternative 2 companies are also low risk for listeria, but only use a lethality step to reduce or eliminate listeria. Alternative 2b and 3 establishments are more at risk for listeria and are required to test FCS to verify sanitation in the environment. Alternative 2b companies use AMAP to limit or suppress listeria growth in product. Finally, Alternative 3 companies rely only on sanitation to control listeria in the environment, as well as on the product — this includes deli meat and hot dogs.
While FCS — such as slicers, dicers, and ovens — testing is required for only alternative 2b and 3 companies, FSIS encourages all establishments to do it. “You can test specifically for LM or you can test for any listeria species,” says Natrajan. “The difference is if you are going to test for LM, then you should be ready to have a test and hold in place. Also, that product may no longer reach commerce should its FCS test positive for LM — if a FCS tests positive, then automatically the product is also positive.” However, when you test FCS for any listeria species, that opens up the possibility of contamination, but not necessarily having to get rid of the product because the product is not yet considered adulterated. Should testing reveal positive results for LM or other listeria species, establishments are expected to take corrective action to address it and mitigate product adulteration.
FSIS offers companies falling under its jurisdiction with resources and documents, including how to sample, how to validate samples, and how to validate sanitation, on its website. Additionally, the FSIS website offers a frame/mock verification testing schedule. “For instance, let’s assume you’re a small, deli meat producer. What kind of sampling should you have,” asks Natrajan. “This FSIS tool provides this information, as well as info on environmental and finished-product testing.”
What Happens When LM Is Found?
If a product or FCS tests positive for LM, the product will be considered adulterated. The U.S. has zero tolerance for LM and the product must be reworked to eliminate the pathogen before it can enter commerce or the product must be destroyed.
The next step is adequately named, “seek and destroy.” The mission is to find out where, whether in the environment or on a FCS, the bacteria is harbored and eliminate it. “If there's one, there are going to be more,” says Natrajan. “We brought it in and we provided it a perfect environment to grow. Bacteria’s needs are very similar to humans — food, water, shelter, warmth — a food processing plant is the perfect place for the multiplication of listeria.”
When positives for LM are found, seek and destroy should become the goal of the entire plant. In the case of Keystone Foods, each department — such as QA, sanitation or food safety — works alone to collectively find the source of LM. “The best programs find LM,” says Natrajan. “When you’re producing thousands of pounds of product each day, the possibility of having negative test results day in and day out over the course of months indicates your program isn’t working. A working program has faults, those faults are found, and then they are eliminated.”
Does Seek And Destroy Work?
The seek-and-destroy approach has helped identify some high-risk areas and conditions in food plants including, equipment design, construction, product debris moving to difficult-to-clean places, shift changes and cleanups, high-pressure cleaning, and excessive rinsing.
However, this approach is reactive, not proactive or preventive. To put these programs into a preventive controls lens, it’s important to review programs, samples, and sanitary design, make necessary changes to them, then ensure those changes can mitigate risks through verification activities. This may seem like common sense now, but it was, and continues to be, a lengthy learning process to find out where bacteria actually live. “If you remember, years ago, a Sara Lee LM recall,” reflects Natrajan. “What was the cause of LM entering the product? A plant was undergoing construction and air conditioning vents were harboring bacteria, which subsequently entered the product. These are the types of things we’ve learned over the years; now knowing they exist and preventing them is the norm. We will continue to learn where to place preventive controls as time passes and we gain knowledge and experience.”
About Nandini Natrajan
Nandini Natrajan is employed as Sr. Director for Global Science Operations for Keystone Foods; a global food processing company based in West Chester, PA. She has over 20 years of experience in the area of Food Safety and Risk Mitigation. Nandini holds a Master’s degree in Food Science from the University of Delaware and a Ph.D. in Food Microbiology from North Carolina State University. Nandini sits on research advisory committees on public health and food safety for various Trade Organizations. Additionally, Nandini served two terms on a National Advisory Committee on Microbiological Criteria for Foods, working on Control Strategies for Reducing Foodborne Norovirus infections. Nandini serves as community board member on Virtua health system’s Quality and Safety committee In NJ.