Risk Assessment Reinforces That Keeping Ready-To-Eat Foods Cold May Be the Key to Reducing Listeriosis

WASHINGTON, D.C. -- The Food and Drug Administration (FDA) of the Department of Health and Human Services (HHS) has released the risk assessment on the relationship between foodborne listeriosis and human health. This scientific analysis outlines clear measures industry, retailers and consumers can take to dramatically reduce the risk of this foodborne pathogen.

The FDA regulates nearly all foods except for meat and poultry-based foods (and some egg-based products), which are regulated by the Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture (USDA).

The past several years have seen continuing improvement in the control of Listeria monocytogenes, the pathogen that causes listeriosis, in a wide variety of ready-to-eat foods. For example, this assessment follows an October 2003 FSIS release of findings indicating a "25 percent drop in the percentage of positive Listeria monocytogenes samples and a 70 percent decline compared with years prior to the implementation of the Hazard Analysis and Critical Control Points (HACCP) system." Much of the reduction is associated with new regulatory steps and a variety of actions taken by the food industry to address the presence of Listeria monocytogenes in their products.

The FDA risk assessment shows that controlling the growth of Listeria monocytogenes in ready-to-eat foods is the key to preventing listeriosis, a serious infection in humans. Two simple practices can further reduce the risk of illness or outbreaks from the Listeria monocytogenes by more than 50 percent. One practice is to keep refrigerated foods stored at 40 degrees Fahrenheit. The other practice is to use perishable items that are precooked or ready-to-eat as soon as possible. Similar reductions in the risk of listeriosis from the consumption of higher risk foods can also be achieved by reformulating products so that they no longer support the growth of the microorganism, a food safety strategy that some in industry have already undertaken.

"This risk assessment clearly demonstrates that manufacturers, retailers, and consumers alike can all take simple actions to drastically reduce the risk of listeriosis," said Mark B. McClellan, MD, PhD, FDA commissioner. "To minimize the risk of this foodborne illness, perishable and ready-to-eat foods should be transported, offered for sale, kept at 40 degrees Fahrenheit, and used as quickly as possible. Food manufacturers should build on their progress to reformulate and monitor susceptible foods to prevent significant levels of Listeria monocytogenes."

The initiative included 23 separate risk assessments and analysis of the relative risks of serious illness and death associated with consumption of 23 types of ready-to-eat foods. It also included public comments received on the draft risk assessment that was completed in 2001. Some of the data for the risk assessment was provided by the USDA's Food Safety and Inspection Service. The FDA is working closely with USDA, the U.S. Centers for Disease Control and Prevention (CDC), and other health authorities to combat foodborne illnesses such as listeriosis.

This new scientific information will allow FDA to improve the effectiveness of food safety programs, technological advances in the production of foods and regulatory actions to ensure that this risk to the public is minimized in the future.

The risk assessment evaluated the risks associated with many foods including these food categories: seafood, produce, meats, dairy products and deli-type salads. In examining these closely, FDA showed that five factors are important in measuring the public health impact to consumers from foodborne listeriosis. These factors are: (1) amounts and frequency of consumption of a ready-to-eat food; (2) frequency and levels in a ready-to-eat food; (3) potential of the food to support growth of the bacterium during refrigeration; (4) refrigerated storage temperature; and (5) duration of refrigerated storage before consumption. Therefore, FDA will focus on these factors, individually and as a group, to develop an action plan to identify additional measures to reduce the risks of listeriosis. The action plan will consist of the following:

Guidance for processors, retailers, and food service/institutional establishments;

Training/technical assistance;

Consumer and health care provider information and education;

Enforcement and regulatory strategies;

Disease surveillance and outbreak response;

Research needs.

The results of the risk assessment reinforce past studies that foodborne Listeria monocytogenes is rare and declining, but potentially life threatening when illness occurs. Initially estimating that Listeria monocytogenes causes 2,500 serious illness and 500 deaths each year, the CDC's Food Net program has recorded over a 40 percent decrease in the incidence of foodborne Listeria monocytogenes infections during the past five years. Foodborne illness caused by listeriosis in pregnant women can result in miscarriage, fetal death, and severe illness or death of a newborn infant. Others at risk for severe illness or death are older adults and those with weakened immune systems.

To more fully inform manufacturer, retailers and consumers, FDA, FSIS, and CDC are scheduling a public meeting on December 4, 2003, at which time the risk assessment will be presented and the public will have an opportunity to ask questions or offer comments related to the results and interpretation of the risk assessment.

The risk assessment reemphasizes that L. monocytogenes grows at refrigerator temperatures above 40 degrees F and this increases the risk of listeriosis; therefore, in the interim, FDA and CDC are advising all consumers to store ready-to-eat foods at 40 degrees F or lower, and to consume perishable and ready-to-eat items soon as possible.

The following additional advice is provided for pregnant women, older adults, and people with weakened immune systems as who are at higher risk for foodborne disease, including listeriosis.

Do not eat hot dogs and luncheon meats, unless they are reheated until steaming hot.

Do not eat soft cheese such as Feta, Brie, and Camembert cheeses, blue-veined cheeses, queso blanco, queso fresco, and Panela unless it is labeled as made with pasteurized milk.

Do not eat refrigerated pates or meat spreads. Canned or shelf-stable pates and meat spreads may be eaten.

Do not eat refrigerated smoked seafood, unless it is contained in a cooked dish, such as a casserole. Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna, or mackerel, is most often labeled as "nova-style," "lox," "kippered," "smoked," or "jerky." The fish is found in the refrigerator section or sold at deli counters of grocery stores and delicatessens. Canned or shelf-stable smoked seafood may be eaten.

Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.

Of note, the recommendation not to eat soft cheese unless it is labeled as made with pasteurized milk reflects a change from previous consumer advice for at-risk consumers not to eat soft cheese at all. Newer data about the contamination of cheese indicates that the risk is not in all soft cheeses, but specifically in cheese made from unpasteurized milk. This reflects the efforts of the dairy industry and FDA during the past several years to develop effective programs to control Listeria monocytogenes in soft cheeses.

Finally, this risk assessment is an important milestone and tool in better understanding this foodborne hazard and making substantial and significant steps to reduce its adverse impact on the public health. Accordingly, FDA is acting under its responsibility to protect the public health and is on target to achieve the Administration's overall Healthy People 2010 goals for national health promotion and disease prevention, to reduce foodborne listeriosis by 50 percent by the end of the year 2005.

The risk assessment is available on the FDA web site at http://www.cfsan.fda.gov, www.foodsafety.gov, and at www.foodriskclearinghouse.umd.edu.

Source: FDA