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March 7, 2008
On February 7, 2008, FDA issued two draft guidances (Draft Guidance for Industry: Control of Listeria monocytogenes in Refrigerated or Frozen Ready-To-Eat (RTE) Foods and Draft Compliance Policy Guide, Sec. 555.320, Listeria monocytogenes). The following questions and answers will be useful in answering questions about these guidances.
The Food and Drug Administration (FDA) is issuing for public comment two draft guidances regarding L. monocytogenes in ready-to-eat (RTE) foods. FDA is also announcing a public meeting to be held on March 28, 2008, from 9 a.m. to 4:30 p.m. at the Harvey W. Wiley Federal Building in College Park, MD to discuss one of the draft guidances (i.e., the draft Compliance Policy Guide (CPG)).
One of the draft guidances is directed to the food processing industry and, when finalized, would provide guidance on how to control the food processing environment to prevent foodborne illness from the consumption of refrigerated or frozen RTE foods contaminated with L. monocytogenes. The second is a draft CPG directed to FDA staff and, when finalized, would establish FDA's enforcement policy regarding L. monocytogenes in food.
FDA guidance describes the agency's current thinking on a topic and should be viewed only as recommendations. FDA guidance does not establish legally enforceable responsibilities.
For the purpose of the two guidances, FDA considers a RTE food as one that is typically consumed without cooking by the consumer, or that appears suitable for consumption without cooking by the consumer. Some examples of food that we consider RTE food are milk, cheese, smoked fish, deli salads, and most fruits and vegetables. These are described in more detail in the draft guidance documents (see also Questions 19 and 20).
For the purpose of the two draft guidances, FDA may consider a food to be suitable for consumption without cooking by the consumer even though cooking instructions are provided on the label. Some consumers eat products such as fresh crabmeat, frozen crabmeat, and individually quick frozen (IQF) peas and corn without cooking, because these foods appear to be RTE.
FDA prepared both guidances in follow-up to a scientific risk assessment, which showed that the risk to consumers from the consumption of foods contaminated with L. monocytogenes varies depending on whether the characteristics of the food support growth of the microorganism (high risk) or do not support growth (low risk). The FDA conducted this risk assessment in collaboration with the United States Department of Agriculture's Food Safety and Inspection Service (FSIS), and in consultation with the Centers for Disease Control and Prevention (CDC). The purpose of this assessment was to systematically examine available scientific data and information in order to estimate the relative risk of serious illness and death that may be associated with consumption of different types of RTE foods that may be contaminated with L. monocytogenes. The objective of the guidance document to industry is to describe factors, technologies, procedures, and practices that have been identified as providing control of L. monocytogenes during the manufacture, distribution, marketing, and use of RTE foods.
The guidances will go into effect after FDA considers public comments and issues final guidance including appropriate revisions based on those comments. Although comments may be submitted at any time, the agency is encouraging stakeholders to submit comments by April 7, 2008. Because the processing guidance incorporates many long-standing published recommendations from industry, the agency encourages industry to begin using it as soon as possible, even though it is still considered a draft.
The draft guidance for food processors provides recommendations for controlling the food processing environment to prevent foodborne illness from the consumption of refrigerated or frozen RTE foods contaminated with L. monocytogenes. It complements the enforcement policy outlined in the draft Compliance Policy Guide (CPG). The draft CPG emphasizes that the enforcement policy does not establish an acceptable level of L. monocytogenes in food. The enforcement strategy in the draft CPG does not supersede existing legal requirements, e.g., it is still a prohibited act to prepare, pack, or hold foods under insanitary conditions and food processors are still required to comply with the FDA's regulation governing current good manufacturing practices for human food.
The draft guidance for industry promotes increased corporate responsibility to prevent foodborne illnesses, a goal outlined in the Food Protection Plan. The prevention elements of the Food Protection Plan emphasize the importance of FDA and industry collaboration to prevent the occurrence of food related illness.
Most RTE foods do not contain detectable numbers of L. monocytogenes. For many RTE foods, contamination with L. monocytogenes can be avoided – e.g., through the use of current good manufacturing practices that establish controls for ingredients, listericidal processes, segregation of foods that have been cooked from those that have not, and sanitation. Accordingly, FDA’s guidance to industry provides recommendations for specific controls for preventing contamination of refrigerated or frozen RTE foods with L. monocytogenes.
The guidance includes recommendations for control measures that would prevent any L. monocytogenes present in a finished RTE food from growing to high numbers during refrigerated storage. FDA anticipates that industry will use these recommendations to re-formulate high-risk foods so that the foods become low-risk. For example, a manufacturer could add one or more anti-microbial substances to the food, change the pH (acidity) of the food, or use some combination of chemical formulations such as these to reduce the food’s ability to support the growth of the L. monocytogenes bacteria. FDA is aware that since it released the L. monocytogenes risk assessment, some foods have already been reformulated to reduce the risk that they will support the growth of L. monocytogenes.
As with any agency guidance, FDA’s recommendations are not binding requirements. However, the guidance includes recommendations to monitor the facility for the presence of L. monocytogenes and to establish and implement a written plan for the periodic collection and testing of samples of finished RF-RTE food for the presence of Listeria species or L. monocytogenes.
The draft CPG is intended to provide a clear enforcement policy and regulatory guidance regarding the presence of L. monocytogenes in certain foods. In particular, the draft CPG sets forth an enforcement policy that would direct FDA staff to consider legal action if high-risk RTE foods contain detectable L. monocytogenes or if low-risk foods contain 100 or more cells of L. monocytogenes per gram of food.
The draft CPG emphasizes that the enforcement policy does not establish an acceptable level of L. monocytogenes in food. The enforcement strategy in the draft CPG does not supersede existing legal requirements. For example, it is still a prohibited act to prepare, pack, or hold foods under insanitary conditions, and food processors are still required to comply with the FDA's regulation governing current good manufacturing practices for human food.
FDA will review the available evidence on a case-by-case basis to determine if a food is a high-risk RTE food that supports growth of L. monocytogenes or a low-risk RTE food that does not support the growth of this organism over the entire shelf-life of the product.
For high-risk foods, FDA uses an analytical method it developed to detect 1 cell per 25 grams (g) of food (equivalent to 0.04 cells/g) (available online at
FDA BAM Chapter 10: Detection and Enumeration of
Listeria monoctyogenes in Foods).
For low-risk foods, FDA uses a method available from the International Organization for Standardization
(ISO 11290-2:1998(E)) (available from ISO; see
ISO 11290-2:1998
).
The enforcement policy in the draft CPG clarifies which foods support the growth of L. monocytogenes; this will help ensure that FDA resources are focused on these high-risk foods. FDA anticipates that it may be able to increase the number of samples that it periodically collects and tests for L. monocytogenes to verify compliance with the limit for this microorganism in low-risk RTE foods while it continues to focus its inspection and outreach efforts on facilities manufacturing high-risk RTE foods.
L. monocytogenes is a pathogen that is widespread in the environment and may be introduced into a food processing facility. It can contaminate foods and cause a severe, life-threatening illness called invasive listeriosis, particularly in fetuses and neonates who are infected after the mother is exposed to L. monocytogenes during pregnancy. L. monocytogenes can also cause a severe, life-threatening illness in the elderly, or individuals with decreased immune function.
Listeriosis, a serious infection caused by eating food contaminated with the bacterium L. monocytogenes, has been recognized as an important public health problem in the United States. A person with listeriosis will experience fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. If infection spreads to the nervous system, symptoms such as headache, stiff neck, confusion, loss of balance, or convulsions can occur. Infected pregnant women may experience only a mild, flu-like illness; however, infections during pregnancy can lead to miscarraige or stillbirth, premature delivery, or infection of the newborn.
Most outbreaks and sporadic cases of listeriosis are foodborne and overwhelmingly associated with RTE foods. Cases and outbreaks have been associated with RTE foods that contain high numbers of L. monocytogenes due to the ability of the food to support the growth of this microorganism during refrigerated storage.
Foods that pose the highest risk to consumers are RTE foods that support the growth of L. monocytogenes. Examples of RTE foods that support the growth of L. monocytogenes include: milk; high fat and other dairy products (e.g., butter and cream); soft unripened cheeses (greater than 50 percent moisture, particularly those made from unpasteurized milk) (e.g., queso fresco, cottage cheese and ricotta cheese); cooked crustaceans (e.g., shrimp and crab); smoked seafood (e.g., smoked finfish and mollusks); certain vegetables (such as cabbage); non-acidic fruit (such as melons); and some deli-type salads and sandwiches (particularly those containing seafood and those prepared at retail establishments without acidification and/or the addition of antimicrobial substances).
Foods estimated to pose the lowest risk to consumers are foods that do not support the growth of L. monocytogenes. The organism 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; the food is frozen; or the food is formulated to have certain combinations of pH, water activity, and antimicrobial substances. Examples of low-risk RTE foods that do not support the growth of L. monocytogenes include: fish that are preserved by techniques such as drying, pickling, and marinating; ice cream and other frozen dairy products; processed cheese (e.g., cheese foods, spreads, slices); cultured milk products (e.g., yogurt, sour cream, buttermilk); hard cheeses (less than 39 percent moisture) (e.g., cheddar, Colby, and Parmesan); some deli-type salads; some vegetables (such as fresh carrots); and crackers, dry breakfast cereals, and other dry foods.
RTE foods can be contaminated with L. monocytogenes if ingredients used to manufacture the foods are contaminated with L. monocytogenes and are not treated to destroy the organism, or if L. monocytogenes is allowed to contaminate the RTE food because of improper sanitary conditions or practices during manufacturing, distribution, or marketing. L. monocytogenes is found in soil and water. Vegetables can become contaminated from the soil or from manure used as fertilizer. Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin such as meats and dairy products. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing, such as soft cheeses and cold cuts at the deli counter. Unpasteurized (raw) milk or foods made from unpasteurized milk may contain the bacterium. L. monocytogenes is killed by pasteurization and cooking; however, in certain ready-to-eat foods such as deli meats and smoked seafood, contamination may occur after cooking but before packaging.
Wash raw vegetables thoroughly before eating; keep uncooked meats and seafood separate from vegetables and from cooked foods and RTE foods; avoid unpasteurized (raw) milk or foods made from unpasteurized milk; wash hands, knives, and cutting boards after handling uncooked foods; and consume perishable and RTE foods as soon as possible.
For more information on FDA's recent activities visit Current FDA Activities Related to the Listeria monocytogenes Action Plan.
