TORONTO — Two sessions at the International Association for Food Protection (IAFP) conference dealt with the complexities of Listeria and performance standards.

Sanjay Gummalla, from the American Frozen Food Institute (AFFI), said the premise that a single cell of Listeria monocytogenes can cause disease does not have scientific basis.

Gummalla previously co-authored an opinion article on Listeria policy in the U.S. and Canada. As frozen foods do not support Listeria growth, they are considered low risk but the older population is an expanding at-risk group and the pathogen can grow at refrigeration temperatures.

The U.S is planning to update draft guidance this year while Health Canada recently released a revised policy for Listeria monocytogenes in ready-to-eat (RTE) foods.

Move away from zero tolerance
Gummalla said the U.S. was in a “default zero tolerance paradigm” and while Canada had taken a risk-based approach focused on the vulnerable population, the U.S. continued to have a hazard based approach.

Attendees heard that Listeria recalls are happening because of positive findings but there is no enumeration so contamination levels are unclear and data is missing. Zero tolerance is not addressing the root causes, it is treating all RTE food as presenting the same risk and limiting implementation of robust seek and destroy verification measures he said.

Gummalla covered how Listeria could be getting into production facilities, its persistence, and environmental monitoring programs.

He said it was a misconception that a good sanitation program is one without any positives. He also questioned whether seek and destroy was the right approach. What were acceptable positive rates in the environment and was there a need to mandate food contact surface testing?

Finished product testing is not an alternative to robust and routine environmental monitoring and sampling should be done well into the production process and not right after the sanitation cycle, added Gummalla. 

Producers of RTE foods must ensure products are formulated, processed, packaged, and stored correctly as they are intended to be consumed without additional cooking steps or processes to eliminate or reduce pathogens. These foods have been associated with illnesses and outbreaks resulting from poor sanitation, inadequate processing, abuse during storage, or modified exposure before consumption that may support growth of pathogens to high enough levels to make people sick.

Not-RTE (NRTE) foods require validated preparation instructions on the label to help consumers with preparation to ensure that the food is safe. There is increasing regulatory and customer pressure to tighten microbiological requirements on NRTE products because of concern about deviation from the preparation instructions.

Standards in different sectors
Another session at the conference looked at performance standards, which are the pathogen reduction levels that must be attained during processing to assure food safety. In some cases, limits have been created over decades of scientific testing. These standards vary depending on the food category.

They can be established based on scientific literature, studies performed by companies, regulatory requirements, or by using risk-based pathogen modeling. For many products, specific guidance for a performance standard is not available because of a lack of adequate data to establish the log reduction necessary to protect public health. In such cases, there is a need for a multiple-hurdle concept.

Stephanie Nguyen, of ConAgra Brands, spoke about performance standards for RTE meat and plant proteins, canned foods and frozen vegetables. Nguyen said there are challenges around making sure any data being used also applies to cell-based meat and plant based or alternative proteins. She added it is important to consider how consumers are handling products, the desire for minimally processed foods, and new technologies like non-thermal processing.

Rico Suhalim, of PepsiCo, covered juices and snacks, including low-water activity foods. Suhalim said people need to know the risk and how to control the hazard, with work potentially extending to suppliers and emphasized the role of validation and challenge studies.

Aaron Uesugi from Mondelez International said, unlike the other areas, there wasn’t really consensus on a performance standard for baked goods or chocolate and the targeted log reduction. Uesugi said it was important to consider if input materials are raw or treated, sourcing destinations and potential post-process contamination.

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