Although Listeria monocytogenes (Lm) is a serious food risk, particularly in ready-to-eat (RTE) foods, regulations for presence and tolerance levels of the pathogen vary between countries. The U.S. holds a zero-tolerance level for Lm in RTE foods; Canada’s regulations categorize foods based on their potential to support Lm growth; and the European Union recently issued a draft regulation updating and tightening its regulation on Lm in ready-to-eat (RTE) foods.
United States. As mentioned, both the FDA and USDA take a zero-tolerance policy for Listeria monocytogenes in RTE foods meaning that no detectable level of this pathogen is allowed in products intended for consumption without further cooking. This policy applies particularly to products that support the growth of Listeria, such as deli meats and soft cheeses. Thus, an establishment producing post-lethality exposed RTE products must control the pathogen through a HACCP plan or otherwise prevent its presence in the processing environment through a Sanitation SOP or other prerequisite program.
- The FDA also issued Guidance on Control of LM in RTE Foods to which those who manufacture, process, pack, or hold RTE and fall under the PC Rule are subject. The guidance is intended to assist in measures that can significantly minimize or prevent the Lm contamination of RTE food when the food is exposed to the environment prior to packaging and the packaged food does not receive a treatment or control that would significantly minimize Lm. The FDA is also in the process of developing a new compliance policy guide for Lm which is expected to be released by December 2024.
- The USDA FSIS also maintains a zero-tolerance policy for Lm in RTE meat and poultry products, for which it continues to strengthen programs and recommendations to reduce or eliminate Lm from RTE products. The basis of the USDA regulations is CFR § 430.4 which states that an “RTE product is adulterated if it contains L. monocytogenes, or if it comes into direct contact with a food contact surface that is contaminated with L. monocytogenes.”
Canada. In 2023, Health Canada updated its “Policy on Listeria monocytogenes in Ready-to-Eat Foods,” which superseded the 2011 version. A key aspect of the updated policy is its emphasis on environmental sampling in post-process areas where RTE foods are exposed to the environment prior to packaging. It distinguishes between two categories of foods, based on their potential to support Lm growth under reasonably foreseeable conditions of distribution, storage and stated shelf-life:
- Category 1: RTE foods which support the growth of Lm, so detection may trigger a serious “Health Risk 1” concern.
- Category 2 includes two subgroups: RTE foods in which the growth of Lm may be limited to levels not exceeding 100 cfu/g (2A) and RTE foods in which Lm growth will not occur (2B).
Regardless of the food category, the Listeria policy considers the potential for growth as well as the presence or levels of Lm in RTE foods as factors to determine the health concern that the food poses to consumers. The intended consumers of the RTE foods (for example, vulnerable populations) are also considered in determining the health concern.
European Union. The EU’s recently issued draft regulation amending Regulation (EC) No 2073/2005 was developed to “guarantee the same level of public health protection from production to distribution for ready-to-eat foods, other than those intended for infants and for special medical purposes, that are able to support the growth of Listeria monocytogenes.”
This draft sets food safety criterion as being “Lm not detected in 25g” applicable to all foods placed on the market during their shelf-life for which it has not been demonstrated that the level of Lm will not exceed 100 cfu/g throughout the food’s shelf-life. The new policy would be effective no earlier than January 2026.
The EU draft states that these levels were set due to the scientific recognition that only ingestion levels of or above 100 cfu/g are potentially injurious to the health of consumers (other than those intended for infants and for special medical purposes). So, foods able to support the growth of Lm during their shelf-life need risk mitigation measures.
As this range of regulation shows, each country has set its own requirements for the presence and prevention of Lm in RTE foods with its own rationale for doing so. If you sell product into only one country/region, you can focus on the specific regulations there. But if you export to or import from others, you are best advised to produce to the lowest tolerance level and require the same of your suppliers.
The various regulatory approaches to Lm indicate that there is no single clear approach to manage Lm risk on which all regulatory bodies can agree. However, we are generally seeing that wherever a country sits on this spectrum of Lm control, the changes are generally in a more conservative direction. This is not surprising given that listeriosis, while rare, has a high mortality rate.
