AFFI looks at current detection methods for public health, regulatory policy

September is Food Safety Education Month and, in recognition, the American Institute of Frozen Foods (AFFI) and the International Fresh Produce Association (IFPA) will host a virtual conference Food Security Forumwhere they will bring together global research experts, industry professionals and food safety policy makers to discuss emerging issues related to non-culturable foodborne pathogens.

Enteric viruses such as hepatitis A, noroviruses and protozoan parasites such as Cyclospora and Cryptosporidium are foodborne pathogens associated with different types of foods and have been implicated in outbreaks. Concerns about these pathogens have led to calls for more systematic testing and monitoring of products throughout the food supply chain; however, the detection of these pathogens has several limitations.

Food Safety Forum speakers will discuss the technical challenges and regulatory issues associated with detecting these pathogens and interpreting the results.

Here are excerpts of interviews with Jennifer McEntire, Chief Food Safety & Regulatory Officer, IFPA, and Sanjay Gummalla, Senior Vice President of Scientific, AFFI, discussing the importance of the forum and scientific discussions of the point from a food safety and public health perspective.

Question: Why is the Food Safety Forum now addressing non-culturable foodborne pathogens and why are AFFI and IFPA encouraging participation from industry, government and academia?

McEntire (IFPA): As concern grows over the prevalence of these pathogens in food, they present distinct detection issues not seen with bacterial pathogens. This forum will delineate the differences between bacterial and non-culturable pathogens such as Hepatitis A, Norovirus and Cyclospora. For example, they cannot be propagated by pre-enrichment, selective enrichment, or selective plating, which are gold standards used in the identification of bacterial pathogens such as Salmonella Where Listeria. Raising awareness about this is relevant for all food safety professionals.

Gummalla (AFFI): Unlike bacterial pathogens which can be cultured in large numbers in a laboratory, enteric viruses must be isolated from food or the environment by concentration and purification, followed by nucleic acid extraction, before a method of detection such that PCR can be applied. The forum will help attendees better understand these steps and the implication of positive outcomes, as well as regulatory and public health considerations. All stakeholders should have a better understanding of this topic as demands for food product testing increase.

​Question: Do these pathogens grow in food? If we can’t culture these pathogens and they don’t grow in food, how can we determine contamination?

Gummalla (AFFI): No, they don’t grow in food and that’s a good thing. But since these pathogens cannot be cultured, the question that must be asked is: “is being able to detect a fragment of nucleic acid synonymous with contamination?” While a suspected bacterial pathogen such as E.coli Where Listeria monocytogenes can be cultured in the laboratory to confirm their presence and viability, such a possibility does not exist with non-culturable pathogens. Instead, we use PCR-based methods, such as testing for SARS-CoV-2 in clinical settings.

McEntire (IFPA): In the FDA’s BAM detection protocol for Cyclospora, the agency outlines some PCR thresholds, but questions remain about the reliability of PCR testing in foods where these pathogens are both heterogeneously distributed and cannot occur only in small numbers. This situation leads to a complex and ambiguous regulatory interpretation of “what” constitutes “an indicator of contamination” and whether a nucleic acid finding determines contamination or tampering.​

Question: How is sample positivity currently determined?

Gummalla (AFFI): Although a PCR test signal may be positive, evidence of food contamination remains unclear. Additionally, confirmatory approaches can back up the original PCR-based positive result, but none of these methods have been properly verified, published, or routinely used by the technical community.

McEntire (IFPA): For Cyclospora in particular, the organism appears to have a complex life cycle and is only infectious during one phase of its life. So even if there’s a positive PCR, you can’t tell which version of the organism was there, even if it’s viable.

Question: What other components can inform the risk?

McEntire (IFPA): Given the limitations of testing and the uncertainty as to the significance of a positive test for the presence of nucleic acid, there are a range of other factors that must be assessed when considering a test result. potentially positive PCR test. This could include a review of the presence of worker illnesses at the farm or facility, a review of site sanitation, and the use of Good Manufacturing Practices (GMPs) or Good Agricultural Practices (GAPs). It is important to understand the total public health risks to inform food safety decisions.

​​Question: What resources are available to help these communities reduce their risk to these organisms?

Gummalla (AFFI): AFFI recently launched an enteric virus control specialist certification program in partnership with the International Food Protection Training Institute. This includes courses that cover best practices in worker health and hygiene, controlled water use, waste management, and sanitation of equipment and tools. The course is based on AFFI Enteric Virus Control Programa free resource accessible to all fruit and vegetable producers and processors.

McEntire: IFPA and AFFI are working closely with the FDA to support industry prevention strategies for specific product-hazard pairs, including berries and hepatitis A, and we will share any new knowledge or acquired idea. For Cyclospora we have a technical bulletin free for industrial use. But truth be told, we need to better understand this organism and the routes of contamination. We don’t want the industry wasting resources by implementing programs that won’t have an impact.

Question: Why should food safety experts be interested in learning more about non-culturable foodborne pathogens?

Gummalla (AFFI): We are at a crossroads to set important precedents in our approaches to determining ‘indicators of contamination’, ‘tampering’ and attributing the ‘public health risk’ associated with non-culturable pathogens. It is important that all stakeholders in the food safety community understand the limitations of methods, how we assess contamination, as well as regulatory enforcement and public health impact. We are delighted to host the Food Safety Forum and to stimulate scientific awareness, debate and understanding of this difficult topic. We invite food industry professionals to join us virtually on September 21, 2022 at 11 a.m. EST.

​This information was provided by AFFI. For more information, see www.affi.org/food-safety-forum.

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