Researchers have provided alternatives to the zero-tolerance approach used in the United States to manage Listeria in low-risk foods.

The U.S. has this method for all ready-to-eat (RTE) foods, regardless of risk profile, so all positive tests prompt a recall.

“A blanket zero-tolerance policy for all RTE foods provides a very strong disincentive for zone 1 (product contact surface) testing, as well as a significant disincentive for finished product testing. More specifically, the challenge with a zero-tolerance approach for all foods is that all positive test results will lead to a recall, therefore potentially limiting the willingness to frequently sample,” said researchers in the journal Food Control.

“To compensate for moving away from a zero-tolerance approach for low-risk foods, the industry would likely be willing to do a higher frequency of testing, which would enable them to generate and use more data, including next-generation tools, to inform risk-based decision-making, long before committing products to commerce.”

Researchers said there was a need for globally harmonized public health approaches to definitions of RTE and not ready-to-eat (NRTE) foods.

Listeria regulation
Many other countries have microbiological criteria for Listeria monocytogenes of 100 colony forming units per gram for low-risk foods that do not support the growth of the organism.

The US Department of Agriculture’s (USDA) Food Safety Inspection Service (FSIS) approach to meat safety differs from that used by the US Food and Drug Administration (FDA) to assure the safety of other foods.

The American Frozen Food Institute’s (AFFI) Listeria monocytogenes international expert panel was created in December 2018 as part of efforts to merge research and data with scientific thinking on regulatory policies on the prevalence of the pathogen in foods. The panel set out to develop a scientific basis and rationale for Listeria monocytogenes regulation.

“The frozen food industry is committed to advancing food safety practices to prevent and control Listeria monocytogenes. We’re grateful for the insights and guidance from the Listeria monocytogenes international expert panel and believe their new recommendations should guide practical and sustained approaches to Listeria regulatory policy that improve public health,” said AFFI President and CEO Alison Bodor.

Handling Listeria in low-risk foods
Benefits of not recalling low-risk foods that don’t support the growth of Listeria monocytogenes and contain low levels of the pathogen include not wasting industry and regulator resources or losing consumer confidence, decreased food waste, avoiding negative effects on the environment, and avoiding unnecessary costly recalls, according to the study.

Researchers stressed the need for an alternative approach to deal with low-risk foods containing Listeria monocytogenes. Food is low risk if the pH of it is less than 4.4, water activity is less than or equal to 0.92, or it is frozen. Foods satisfying these conditions do not support the growth of Listeria monocytogenes.

This could include using alternatives to the current 2-class presence-absence sampling plans for low-risk foods wher Listeria cannot grow; using big data to better inform microbial risk assessments; performing a risk-benefit assessment, and developing consumer food handling and risk communication strategies.

Researchers said regulatory efforts should be directed at RTE foods that support the growth of Listeria monocytogenes with a multi-pronged approach to control the pathogen needed.

Actions such as a product recall should not be made upon finding low levels (less than 100 CFU/g) in food not supporting growth or an NRTE food unless the plant has a history of violations or recalls, there is evidence of illness linked to the product; there are repeat findings of Listeria monocytogenes in the product or it is targeted to at-risk individuals.

Meanwhile, experts have started a three-week meeting to provide Codex with updated scientific advice on Listeria monocytogenes in RTE foods.

The Joint FAO/WHO Expert Meeting on Microbiological Risk Assessment (JEMRA) will examine new research and data for Listeria in different foods and geographical regions to validate the current risk assessment models and inform risk management approaches to control the bacteria.