Listeria monocytogenes Guidance on Environmental Monitoring and Corrective Actions in At-risk Foods

INTRODUCTION Listeria monocytogenes is a bacterial pathogen that is widely distributed in nature. Listeria monocytogenes is pyschrotrophic1 and can tolerate high salt as well as a wide pH range. The organism has been isolated from many raw agricultural products, raw meat and poultry products, raw milk, and raw aquaculture products. Listeria monocytogenes has been associated with a number of foodborne outbreaks in a variety of refrigerated food products, such as ready-to-eat (RTE) meat, dairy products, processed vegetables as well as fish and seafood (1) (2) (3).


The presence of L. monocytogenes in RTE products is generally known to occur because;

1) there is no lethality step or an insufficient lethality step, so that incoming materials do not receive a process that would be sufficient to eliminate Listeria on outgoing products (e.g., fresh or fresh cut fruit and vegetables);

2) products are intended to undergo a listericidal treatment but are processed incorrectly (e.g., an insufficient thermal process); or

3) the product is exposed to the processing environment, and has been contaminated or recontaminated by from the processing environment.


This guidance will focus on the latter point for refrigerated RTE foods that can support the growth of L. monocytogenes; for clarity, the term “at-risk foods” will be used throughout this document to describe these foods.


About the Authors
This document has been prepared by Richard Brouillette (Commercial Food Sanitation, formerly Mondelez International), David Aggen (retired, formerly Lakeside Foods), Brian Borchert (Sara Lee Corporation), Kurt Buckman (Pinnacle Foods Group LLC), Mark Domanico (retired, formerly Kellogg Company), Judy Fraser-Heaps (Land O’Lakes), Timothy Freier (Cargill), Melinda Hayman (GMA), Timothy Jackson (Nestlé NA), Ai Kataoka (GMA), Joseph Meyer (Covance Laboratories, formerly Kellogg Company), Emily Shoaf (WhiteWave Foods, formerly GMA), and Warren Stone (GMA).


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