FDA Releases Updated Draft Guidance On Controlling Listeria In Ready-To-Eat Foods
The US Food and Drug Administration (FDA) today released an updated draft guidance for the food industry entitled “Control of Listeria monocytogenes in Ready-To-Eat Foods,”
The revised draft guidance is intended for any person who is subject to FDA’s regulation, “Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Human Food,” and who manufactures, processes, packs, or holds ready-to-eat (RTE) foods.
Ready-to-eat food means any food that is normally eaten in its raw state or any other food, including a processed food, for which it is reasonably foreseeable that the food will be eaten without further processing that would significantly minimize biological hazards.
FDA had made available in February 2008 a draft guidance for industry entitled “Control of Listeria monocytogenes in Refrigerated or Frozen Ready-To-Eat Foods.” Since issuing that 2008 draft guidance, FDA conducted rulemaking to amend the current good manufacturing practice (CGMP) requirements in part 110 of the CFR to modernize them and establish them in new part 117.
Part 117 also includes new requirements for domestic and foreign facilities that are required to register to establish and implement hazard analysis and risk-based preventive controls for human food. The new human food preventive controls requirements are part of FDA’s implementation of the Food Safety Modernization Act.
FDA has revised the 2008 draft Listeria guidance to reflect the comments it has received on that draft guidance, the amended CGMP requirements, the new human food preventive controls requirements, and the recommendations of its Food Advisory Committee.
The revised draft guidance is intended to explain FDA’s current thinking on procedures and practices to help food establishments that are subject to part 117 to: comply with the CGMP requirements of part 117 (e.g., for personnel, buildings and facilities, equipment and utensils, and production and process controls) during the production of an RTE food that is exposed to the environment prior to packaging and the packaged food does not receive a treatment or otherwise include a control measure (such as a formulation lethal to L. monocytogenes) that would significantly minimize L. monocytogenes; and comply with certain human food preventive controls requirements regarding environmental pathogens in such RTE foods.
Listeria monocytogenes is an environmental pathogen that can contaminate foods and cause a mild, non-invasive illness (called listerial gastroenteritis) or a severe, invasive illness (called listeriosis), the guidance explained. Although temperatures below freezing prevent the growth of L. monocytogenes, the pathogen can multiply slowly at refrigeration temperatures. As a result, refrigeration is less effective as a control measure for L. monocytogenes than for other foodborne pathogens, such as Salmonella.
Listeriosis is largely associated with RTE foods. It is well established that foods that pose the greatest risk of foodborne listeriosis are those RTE foods that have intrinsic characteristics (such as pH and water activity) that support the growth of L. monocytogenes, whereas the RTE foods that pose the least risk of foodborne listeriosis are foods that have intrinsic characteristics that prevent the growth of L. monocytogenes.
It is also well established that L. monocytogenes does not grow when: the pH of the food is less than or equal to 4.4; the water activity of the food is less than or equal to 0.92; and the food is formulated to contain a combination of factors scientifically demonstrated to be effective in preventing growth (the “hurdles” concept).
Examples of RTE foods that support the growth of L. monocytogenes and that have been found to be contaminated with L. monocytogenes, according to the guidance, are unpasteurized and pasteurized milk, high-fat dairy products, soft unripened cheese, semi-soft cheese and soft-ripened cheese.
An example of an RTE food that does not support the growth of L. monocytogenes, but has been found to be contaminated with L. monocytogenes, is ice cream, the guidance noted.
L. monocytogenes is widespread in the environment, the guidance said. It can be readily isolated from humans, domestic animals, raw agricultural commodities, and food packing and processing environments, particularly cool damp areas, and it has been shown to persist in equipment and the processing environment in harborage sites.
In addition to being able to survive and grow at refrigeration temperatures, L. monocytogenes tolerates high salt concentrations (such as in non-chlorinated brine chiller solutions) and survives frozen storage for extended periods. It also survives acid conditions and is more resistant to heat than many other non-spore forming foodborne pathogens, although it can be killed by heating procedures such as those used to pasteurize milk.
The application of CGMPs and preventive controls requirements to the production of RTE foods can significantly minimize or prevent contamination of an RTE food with L. monocytogenes, the guidance stated.