Food Safety and Inspection Service United States Department of Agriculture Washington, D.C. 20250-3700

News and Information

May 2000

Food Safety and Inspection Service
Revised Action Plan for Control of Listeria monocytogenes for the Prevention of Foodborne Listeriosis

Note: This document is presented for historical purposes. Due to its age, some of the attachments are no longer available.

Summary

On May 5, 2000, President Bill Clinton directed the Secretaries of Agriculture and of Health and Human Services to report back to him within 120 days on steps both Departments would take to significantly reduce the risk of illness and death by Listeria monocytogenes in ready-to-eat foods. The President also directed the agencies to undertake several specific actions in order to accelerate our meeting the Administration's goal of cutting in half the number of illnesses caused by this pathogen by the year 2010. That goal, articulated in the Administration's Healthy People 2010 plan, would further reduce the number of foodborne listeriosis cases from 0.5 cases per 100,000 to 0.25 cases per 100,000. The President noted his belief that all of these actions, taken together, should allow us to achieve that goal by 2005 rather than 2010. (See Attachment 11.)

On February 10, 1999, FSIS held a public meeting to gather information on Listeria monocytogenes and listeriosis associated with ready-to-eat (RTE) meat and poultry products. This was in response to a large outbreak of listeriosis in late 1998/early 1999 attributed to bacteria in a ready-to-eat meat or poultry product and several recalls of meat and poultry products for contamination with L. monocytogenes. At this meeting, experts from FSIS, CDC, FDA, industry groups, and consumer groups shared foodborne illness and product contamination statistics, on-going research and research needs, testing programs, education efforts, and FSIS policy regarding L. monocytogenes in ready-to-eat meat and poultry products. (See Attachment 1.)

In May of 1999, Food Safety and Inspection Service (FSIS) Administrator Tom Billy announced a series of initiatives FSIS was undertaking to reduce the risk of foodborne illness attributed to the pathogen Listeria monocytogenes. The action plan for control of L. monocytogenes was formulated from the information gathered at the February 1999 public meeting. These initiatives included near-term and long-term activities, involving all programs of the Agency, as well as interagency activities. (See Attachment 2.)

This paper provides an update on the action plan for enhanced control of Listeria monocytogenes and thereby for the prevention of foodborne listeriosis. It is intended to serve as a basis for gathering public input on FSIS current thinking.

Background

Listeria monocytogenes is a foodborne pathogen of public health concern as reflected in statistics for severe foodborne illnesses and in national objectives for reducing foodborne illness. Each year, the bacteria cause at least 2,493 cases of listeriosis. Of these, 2,298 persons are hospitalized and 499 persons die. The case fatality rate is high -- 20 deaths per 100 cases of illness. (See Table 1.)

While the nation met its Healthy People 2000 target for reducing foodborne listeriosis, the Healthy People 2010 target is a further reduction from the 0.5 cases per 100,000 baseline of 1997 to 0.25 cases per 100,000. (See Tables 2 and 3.)

Although the Agency is awaiting final results from the interagency Listeria monocytogenes risk assessment, currently available FSIS data indicate that Listeria monocytogenes remains the primary trigger for product recalls. (See Table 4.) FSIS microbiological monitoring data from 1993-99 suggest that hot dogs and luncheon meats are two products of particular concern as vehicles for foodborne Listeria monocytogenes. (See Table 5.) Consequently, the proposed action plan for control of Listeria monocytogenes includes activities directed at further reducing the risks of foodborne illness associated with those products.

FSIS has updated its Action Plan for control of Listeria monocytogenes based on discussions and recommendations of the National Advisory Committee on Meat and Poultry Inspection, public meetings, additional data, and the work of an Agency working group on this topic. This revised Action Plan also considers information provided in a January 2000 petition from the Center for Science in the Public Interest to the Agency. (Attachment 3.)

NEAR-TERM INITIATIVES COMPLETED

• Federal Register Notice on Reassessing HACCP Plans. On May 26, 1999, FSIS published in the Federal Register a Notice advising manufacturers of ready-to-eat meat and poultry products of the need to reassess their HACCP plans to ensure that the plans are adequately addressing Listeria monocytogenes. If this reassessment reveals that Listeria monocytogenes is a hazard reasonably likely to occur in the establishment’s production process, the Notice stated that the hazard then must be addressed in the establishment's HACCP plan. (See Attachment 4.)
  
  In the May 1999 Federal Register Notice, FSIS presented four factors that it believes are relevant in determining whether L. monocytogenes is a food safety hazard reasonably like to occur in processing ready-to-eat products. Those factors are: (1) pathogen levels in raw materials; (2) effectiveness of the lethality treatment (kill step); (3) potential exposure of products to contamination after the lethality treatment; and (4) evidence of product contamination revealed by finished-product testing. In the May 1999 Notice, FSIS stated that reassessments should be completed by June 26, 1999.
  
  Concerns raised by stakeholders after publication of this FR notice included (but were not limited to) whether establishments were required to conduct testing programs in their facilities, what actions inspectors would take against plants on positive results from environmental sampling programs, and the deadline for the reassessment. Although FSIS did not postpone the effective date by which reassessment should have occurred, the Agency did not begin inspection activities to verify plant reassessment until August 1999 (see below).

• FSIS Notice on Listeria monocytogenes Reassessment. On June 17, 1999, FSIS issued FSIS Notice 17-99 to its inspection personnel. This FSIS notice provided the May 1999 Federal Register notice and information regarding the need for manufacturers of ready-to-eat meat and poultry products to reassess their HACCP plans for these products. (See Attachment 5.)

• FSIS Notice on Verifying Reassessment. On August 3, 1999, FSIS issued Notice 23-99, Instructions for Verifying the Listeria monocytogenes Reassessment. The August 1999 FSIS Notice instructed inspectors as to how they should proceed in verifying that establishments conducted the reassessment. (See Attachment 6.)
  
  FSIS inspection personnel performed the verification of reassessment when the Performance-Based Inspection System (PBIS) scheduled a 01 procedure for the ISP activity codes applicable to ready-to-eat meat and poultry products. The two main questions asked of the Technical Service Center about verifying reassessment were: 1) What exactly is reassessment? And 2) What is a ready-to-eat product? Both were addressed in FSIS Notice 23-99; however, many inspection employees consulted with the Technical Service Center for clarification.

• Guidance to Industry on Preventing Listeria monocytogenes Contamination. The Agency complemented its policy clarification documents with guidance to the regulated industry on May 26,1999, when the Agency published the Federal Register Notice advising manufacturers of ready-to-eat meat and poultry products to reassess their HACCP plans for the potential hazard of Listeria monocytogenes. The Agency released guidance materials to aid the regulated industry. The Listeria Guidelines for Industry provided practices that have been used successfully by several meat and poultry establishments to prevent the occurrence of Listeria monocytogenes in ready-to-eat products. (See Attachment 7.)
  
  The guidance was developed using the best scientific and technical information available from government, individual meat and poultry processing establishments, and trade associations. In addition, a number of trade associations produced "best practices" or "good manufacturing practices" that focus on areas such as sanitation, the handling of raw materials, and employee hygiene and are making these documents available to all establishments. The FSIS guidance document complements these materials by focusing on environmental and end product testing.
  
  The FSIS guidance document was made available through the FSIS web page, and was sent to establishments along with the HACCP Generic Models publications applicable to ready-to-eat products from the Inspection Systems Development Division.

• Guidelines for Environmental and Chill Water Brine Sampling. The FSIS Office of Public Health and Science (OPHS) has prepared a document entitled Guidelines for Environmental and Chill Water/Brine Sampling for Listeria, to supplement the previously released industry guidance. The document describes possible procedures for selection and sampling of environmental sites for detection of contamination by Listeria species. The document was posted on the FSIS website in March 2000. (See Attachment 8.)

• Technical Conference on the Sanitation Performance Standards. More than 300 people, including representatives from USDA, industry and associations, attended the December 8, 1999, Technical Conference on the Sanitation Performance Standard Regulation held at the Technical Service Center in Omaha, Nebraska. During this conference, FSIS officials further clarified Agency policy regarding L. monocytogenes in ready-to-eat meat and poultry products and HACCP plan reassessment.

• Use of PFGE Analysis for L. monocytogenes. In FY 99, pulsed-field gel electrophoresis (PFGE) became an invaluable tool for FSIS and other public health agencies for investigations of foodborne listeriosis and often played a key role in identifying contaminated products for recall. PFGE analysis provides a means of subtyping isolated strains of Listeria monocytogenes to determine possible genetic relatedness. PFGE analysis is used to determine a possible connection between an Listeria monocytogenes strain found in a product sample and a human isolate. A standardized laboratory protocol for PFGE analysis of L. monocytogenes was established in December 1998, by the Centers for Disease Control and Prevention (Atlanta, GA). Since that time, the FSIS Special Projects and Outbreak Support Laboratory (SPOSL) in Athens, GA, has routinely performed PFGE subtyping on L. monocytogenes isolates from contaminated ready-to-eat products. PFGE data is submitted to the CDC database via the PulseNet system.

• Refined Laboratory Methodology for L. monocytogenes. On November 10, 1999, the OPHS Microbiology Division released a refined laboratory methodology for detection and identification of L. monocytogenes. The methodology described in the FSIS Microbiology Laboratory Guidebook, Chapter 8, Revision 2 (11/08/99), was officially implemented in FSIS laboratories on 11/17/99. The refined methodology reduces the analytical time required for determining potentially contaminated products by at least two days.

• Collection of Intact Samples Only. The FSIS Sampling Coordination Team is in the process of revising the ready-to-eat sampling program to provide a tool for inspectors to use microbiological sampling as part of their HACCP verification activities. The first step in updating the program was to require, beginning in July 1999, that all samples collected be intact packages. Previously, inspectors had been permitted to aseptically open a final package and remove the amount of product required to do the requested analysis. If a non-intact sample was found to be positive for a microbial hazard, regulatory action was not taken on that specific lot, because the sample could have been contaminated during the sampling process. Instead, an intact follow-up, or verification, sample was taken from the same product. That follow-up sample would trigger regulatory action if it were confirmed positive for Listeria monocytogenes.

• Direct Final Rule on Additives. On January 20, 2000, FSIS published a direct final rule in the Federal Register to increase permissible levels of sodium diacetate in meat and poultry products as an inhibitor of the growth of certain pathogens. Also, the use of sodium lactate and potassium lactate in meat and poultry products (except infant formulas and infant food) is permitted for the purpose of inhibiting the growth of certain pathogens. This rule became effective March 20, 2000. FSIS expects that establishments choosing to use these substances 1) will reassess their HACCP plans for these products, as formulations will be changed; and 2) where these substances are utilized to inhibit the growth of pathogens, will modify their HACCP plans to establish the use of the substance as a CCP, or incorporate the use into an existing CCP. (See Attachment 9.)

• Review of enforcement strategy. FSIS is engaged in an ongoing review of enforcement strategies to ensure that ready-to-eat products are not contaminated with pathogens. Immediate actions by FSIS focus on confirming the adequacy of plant measures to remove products from consumer channels and stress the responsibility of the plant to determine why its HACCP and other systems failed to prevent the production and shipment of unsafe products. Additional actions include follow-up testing and inspection activities to confirm that the plants have made appropriate changes in their HACCP systems and other inspection to prevent the recurrence of problems. The current enforcement strategy includes withholding and suspending inspection to prevent the shipment of products when plant controls cannot ensure that the products are not adulterated.

• Consumer Education. FSIS is targeting educational activities to reach those individuals who are at risk of developing listeriosis, including pregnant women, newborns, the elderly, and persons with weakened immune systems.
  
  Video News Releases. In February and again in May of 1999, a video news release (VNR) about listeriosis and safe food practices for these at-risk groups was distributed via satellite through the USDA Television Service. The agency paid for tracking of the VNR in May and learned that 11 television markets had downlinked the VNR, reaching an estimated 617,000 viewers. The VNR was then re-edited and produced as a stand-alone educational video for use at seminars and in waiting rooms at clinics and other medical centers. The videos are being distributed to targeted educators and health professionals around the country.
  
  Brochure. In May 1999, the Food Safety Education Staff produced a publication, Listeriosis and Food Safety Tips. The brochure, available in both English and Spanish, defines listeriosis and its symptoms, and provides steps to protect against illness from cross-contamination that is associated with Listeria. Two hundred thousand copies of the brochure were produced. Distribution is underway to food safety educators, and other information multipliers. It was widely advertised via many key electronic distribution lists for food safety educators and health professionals. The brochures can be downloaded free from the FSIS Web site. (See Attachment 10.)
  
  The brochures in English and Spanish are available for purchase in single or bulk copies through the Government Printing Office. In September 1999, the Consumer Information Center (CIC) in Pueblo, Colorado began distribution of 50,000 copies of Listeriosis and Food Safety Tips. The brochure is included in the CIC catalog widely distributed throughout the country.
  
  Additionally, the brochure has been distributed at conferences where the agency has had an exhibit including the American Dietetic Association, the American School Food Service Association, the American Association of Family and Consumer Sciences, and the National Association of Extension Family and Consumer Sciences. The brochure and video are also promoted in presentations given at national and regional meetings by the Food Safety Education Staff.
  
  Other USDA agencies have also distributed the brochure. At the request of the Food and Nutrition Service (FNS), the brochure was sent to eight regional Women, Infants, and Children (WIC) offices in 1999. The FNS Mid Atlantic Regional office distributed 1,000 copies of Listeriosis and Food Safety Tips to school nurses in the Philadelphia, Pennsylvania, area at a conference in September 1999. In addition, CSREES requested that a packet of brochures and a VNR be sent to each State food safety program leader.
  
  At the request of the National Kidney Foundation (NKF), we sent 1, 500 copies of the brochures to them for distribution at their national meeting in October 1999 and for later use.
  
  On September 21, 1999, a letter signed by the Under Secretary for Food Safety, a copy of the video, and a packet of the brochures, Listeriosis and Food Safety Tips, were mailed to approximately 50 medical and health organizations who have at-risk populations as their members or primary audience. The organizations were encouraged in the letter to create a link from their Web pages to the FSIS Web page for Listeria monocytogenes. Follow-up calls were made to the organizations in November and December 1999 to see if the information was received and to determine how the FSIS Education staff can assist them.
  
  The Food Safety Education staff is currently responding to requests from the States and other information multipliers for the materials. Additional outreach activities targeting Hispanic media and information multipliers are also underway, with the availability of the Spanish version of the brochure.

• Survey of industry practices: FSIS has conducted a survey of plant actions taken in response to the 5/26/99 Federal Register notice, to ensure that plant HACCP plans are adequately addressing L. monocytogenes as a potential hazard in ready-to-eat meat and poultry products. Those conducting the interviews were instructed to document what types of controls are in place, using a number of questions prepared in advance.

FSIS Action Plan in Response to President's Directive

FSIS has now reviewed its action plan for the control of Listeria monocytogenes to prevent foodborne illness, in light of the President's May 2000 directive. (See Attachment 11.) That directive observed that the Department of Health and Human Services, in cooperation with the Department of Agriculture, is conducting a risk assessment on Listeria monocytogenes. The President directed the Secretaries of Agriculture and of Health and Human Services to report back within 120 days on the "aggressive steps you will take to significantly reduce the risk of illness and death by Listeria monocytogenes."

The President in particular directed the Secretary of Agriculture to "complete proposed regulations that include any appropriate microbiological testing and other industry measures" to:

1. Prevent cross-contamination in the processing environment;
2. Ensure that the processing of ready-to-eat products meets appropriate standards; and
3. Ensure that such products are safe throughout their shelf life.

Following is the Agency's current thinking on control of Listeria monocytogenes in ready-to-eat meat and poultry products. The Agency believes that much of this work will be responsive to the President's directives.

• Rulemaking:

A. Performance standards: FSIS intends to publish a proposed rule to establish performance standards for shelf-stable and perishable ready-to-eat products that will address the need to reduce all pathogens. The Agency also intends to propose to require that meat and poultry plants producing ready-to-eat products conduct environmental testing for Listeria ssp. in order to verify their Sanitation Standard Operating Procedures (SSOPs). The proposed frequency would be based on the volume of product produced by the plant.

FSIS believes that available epidemiological data amply support the need to begin rulemaking to enhance control of this pathogen, which has a case-fatality rate of 20 percent. In addition, in January 2000 the Agency received a petition from the Center for Science in the Public Interest asking FSIS to require companies producing ready-to-eat meat and poultry products to test both plant environments and finished products for the presence of the pathogen. (See Attachment 3.) During the rulemaking process, FSIS will consider public input on whether plants should test the plant environment for Listeria spp, should test finished products for Listeria monocytogenes, or should test both the environment and the product.

The proposed performance standards would establish a level of pathogen reduction that plants producing ready-to-eat products would need to meet during their operations in order to produce safe products but would allow the use of customized, plant-specific processing procedures other than those prescribed in earlier, command-and-control regulations. The proposed performance standards will be directed at improving the safety of ready-to-eat products; providing plants with the flexibility to adopt innovative, science-based food safety processing procedures and controls; and providing objective, measurable standards that can be verified by FSIS.

The first set of performance standards, for cooked beef, roast beef, and cooked corned beef products, fully and partially cooked meat patties, and certain fully and partially cooked poultry products, was published as a final rule in the Federal Register on January 6, 1999. These performance standards became effective March 8, 1999. Performance standards for other product categories are in the process of being drafted.

B. Validated handling instructions and/or open dating: FSIS also intends to propose to require that establishments using handling instructions or open dating (e.g., "sell by" or "use by" dates) on product labeling validate the accuracy of the handling/open dating information in their HACCP plans. The proposal will include, for public comment, proposed criteria on the use of open dating in meat and poultry products.

Interest in the potential usefulness of labeling as a public awareness and educational tool to help prevent foodborne listeriosis has grown as understanding of the pathogen and its most vulnerable victims has increased. Those most at risk of serious health complications and death from foodborne listeriosis are persons with incomplete or compromised immune systems, including infants, the elderly with underlying health problems, cancer and kidney patients, and AIDS patients. In addition, listeriosis causes spontaneous, late-term abortions in pregnant women.

If a ready-to-eat product containing a single Listeria monocytogenes cell is stored at refrigeration temperature for an extended period of time from distribution to consumption, there is at least a theoretical risk of illness in an at-risk individual. Inadequate reheating of a ready-to-eat product, therefore, could have potentially significant health consequences for a pregnant young woman, a woman with Alzheimer's in a nursing home, or a man going home to dinner after dialysis. Labeling on handling could heighten public awareness and, in conjunction with educational campaigns, have a positive influence on food handling behavior.

• FSIS finished product testing: The Agency intends to modify its program for sampling and testing ready-to-eat meat and poultry products for Listeria monocytogenes. The Agency's current thinking is that the revised testing program will expand the range of ready-to-eat meat and poultry products subject to testing for the pathogen. The frequency of FSIS verification testing will be based on the testing regime that the plant employs. The more the plant is testing, the less likely it is that FSIS will test.

FSIS accordingly intends to revise the criteria for the FSIS directive on its L. monocytogenes testing program to reflect this change.

Today, ready-to-eat products are sampled and tested for L. monocytogenes according to varying schedules established by a number of testing programs. FSIS began testing selected ready-to-eat products for Listeria monocytogenes in 1987. Testing programs for additional products were added or modified in intervening years. Those regulatory programs were designed to encourage process validation, with the frequency of FSIS testing constrained by available resources.

The implementation of Pathogen Reduction and HACCP requires rather than encourages all manufacturers of ready-to-eat meat and poultry products to validate their processes, and the May 1999 Listeria monocytogenes notice clarified that all manufacturers of ready-to-eat meat and poultry products should reassess their HACCP plans to determine whether they adequately address the hazard from Listeria monocytogenes. FSIS testing programs for Listeria monocytogenes are therefore being revised to verify plant HACCP plans for ready-to-eat meat and poultry products.

Industry guidance: In conjunction with the proposed rule on performance standards, the Agency intends to publish guidance to industry regarding appropriate intervention measures that plants could initiate to reduce the risk of L. monocytogenes from hot dogs and sliced luncheon meats. Available epidemiological information suggests that hot dogs and sliced luncheon meats are two products that are vulnerable to Listeria monocytogenes contamination/growth. The small exploratory survey FSIS has conducted to determine how plants have reassessed their HACCP plans in light of the potential hazard of Listeria monocytogenes will be useful in identifying areas where guidance is needed. We know that one of those areas is in the prevention of cross-contamination, as noted in the President's May 2000 directive.

In-depth verification reviews: On an ongoing basis, FSIS plans to use its revised draft protocol for in-depth verification reviews of the regulatory compliance and scientific validity of a company's HACCP systems. On an ongoing basis, FSIS plans to use its revised draft protocol for in-depth verification reviews of the regulatory compliance and scientific validity of a company's HACCP systems.

Interagency risk assessment: The interagency quantitative risk assessment supported by FDA and FSIS will determine the prevalence and extent of consumer exposure to foodborne L. monocytogenes and assess the resulting public health impact of such exposure. The public health impact will be described in terms of risk rankings for the products considered. The risk assessment team has collected data in four areas: the presence of L. monocytogenes in foods, the consumption levels of these foods, information from epidemiological investigations, and data from experimentation that defines the dose-response relationship between this pathogen and human populations with different immune conditions. The results of this risk assessment will provide FDA and FSIS with the scientific information needed to review current programs relating to the regulation of L. monocytogenes contamination in foods. The draft interagency risk assessment underwent internal review in December 1999, with release tentatively scheduled for the summer of 2000.

Specifications for USDA commodity food programs. FSIS will seek to "jump-start" the use of instructional labeling for safe use of ready-to-eat products by working with AMS and other USDA agencies to modify the specifications for ready-to-eat foods purchased for USDA commodity food programs (e.g., school breakfast and lunch, the Women, Infants and Children program). Ensuring that there is appropriate labeling on these products could potentially minimize risks for consumers of those products. Use of the specifications approach has already enabled USDA to prevent consumption of potentially harmful food by some of those most vulnerable to foodborne illness.

Many of these foods are purchased for ultimate consumption by at-risk individuals. For example, the Women, Infants and Children program reaches pregnant women, who are vulnerable to spontaneous late-term abortion from listeriosis. A February GAO report provides support for this approach. It recommends that the Secretary of Agriculture direct the Administrator of FNS to: (1) implement a proposed food safety act database; and (2) provide more specific and complete guidance to school food authorities on safety provisions that could be included in food procurement contracts. The GAO report -- School Meal Programs: Few Outbreaks of Foodborne Illness Reported -- was requested by Senator Harkin to determine the extent of: (1) foodborne illness outbreaks related to meals served in schools; (2) USDA-donated foods in schools being removed, replaced, or disposed of because of a potential to cause foodborne illness; and (3) USDA established procurement policies and procedures for ensuring the safety of foods it donates to the programs.

• Public messages for at-risk consumers: The Agency will work with other agencies within USDA (specifically, the Food and Nutrition Service) and with FDA and constituent groups to develop appropriate public messages for susceptible populations regarding the consumption and preparation of ready-to-eat foods that pose a significant risk from L. monocytogenes. One key message is that ready-to-eat products for consumption by high-risk populations should be heated.

• Consumer education: FSIS will use the information in the interagency risk assessment to develop a consumer education campaign to focus on proper refrigeration temperatures and steps to prevent temperature abuse during food preparation in the home. This campaign will also include specific advice to heat ready-to-eat meat and poultry products that will be consumed by high-risk populations.

LONG-TERM INITIATIVES

• Research: At the request of FSIS, ARS has designed a study to examine prevalence of L. monocytogenes in a ready-to-eat product (hotdogs) supplied by volunteer plants over a 12-month period. Product will be held at a temperature representing typical retail storage and at an "abuse" temperature, and will be tested for the presence of L. monocytogenes at several time points over a 3-month period. ARS also proposes to subtype and enumerate bacteria in positive samples. Approximately 12 members of the ready-to-eat manufacturing industry are participating in the study on condition of anonymity. The product samples for research will not be marketed.

This study will produce data that will address several important information gaps, including the prevalence of contaminated products in the marketplace, the effect of "grow out" on detection of Listeria monocytogenes during shelf life, and counts of Listeria monocytogenes that actually occur in commercially packaged products over their shelf-lives, among others.

UNDER DISCUSSION:
ADDITIONAL ACTIVITIES TOWARD PREVENTING FOODBORNE LISTERIOSIS
(MEAT AND POULTRY PRODUCT FOCUS)

• Agency Review of Product Destined for Vulnerable Consumers. Under this initiative, FSIS -- in cooperation with FNS, AMS, and perhaps one or more states -- would conduct a nationwide review of products purchased for USDA commodity programs in transport and distribution channels (including warehouses). As noted above, listeriosis is more likely to have serious health consequences for some persons. Pregnant women are at risk of late-term spontaneous abortion. The very young, the very old, and the very ill are also at greater risk of serious health consequences. Enforcement actions, product recalls, and reported illnesses and outbreaks are all indicators that Listeria monocytogenes contamination is a potential hazard on RTE products. Of course, many factors in addition to bacterial contamination determine whether the potential for illness is realized, including conditions during transport and storage, as well as preparation methods and the susceptibility of the individual consumer. Some ready-to-eat products are popular with at-risk populations. Some of those at-risk populations consume ready-to-eat products purchased through USDA commodity programs in cooperative relationships with the states. Examples include the School Lunch Program and the Women, Infants and Children (WIC) program. Although the intensive review would include microbial sampling and testing, it would also include in-depth review of other conditions, including ambient temperature, product temperature, and sanitation indicators. The purpose of such a review would be to gain information valuable for Listeria monocytogenes control. The findings of the review could lead to many other improvements as well, including tightened product specifications, improved tracking systems and the development of guidance materials for technical and consumer audiences. It is to be hoped that the findings of such a review would confirm the safety of foods purchased for USDA commodity programs; however, it might uncover problems that would need to be corrected. Timeframe: FY 2001-2002.

• Irradiation. The feasibility of using irradiation as a tool for reducing Listeria monocytogenes levels, thereby preventing foodborne illness, depends largely on consumer acceptance of the technology. More widespread industry application is dependent on consumer acceptance and, of course, consideration of costs. Recent rulemaking from FDA and USDA will allow processors to irradiate refrigerated or frozen uncooked meat, meat byproducts, and certain other meat food products. In consideration of a petition from NFPA to FDA, future rulemaking may consider allowing irradiation of hot dogs and luncheon meats, which are considered to be relatively high risk with respect to Listeria. The resistance of Listeria monocytogenes to radiation is comparable to that of Salmonella when product differences such as water activity, temperature (chilled or frozen product), and the level of ambient oxygen are considered.

Benefits. Ionizing radiation passes through food in the form of radiant energy, which does not leave a residue, substantially diminish the nutrient quality, substantially raise the food temperature, or affect physio-chemical properties so that raw foods maintain the raw appearance. The primary benefits are the extension of shelf life and reduction of microbial pathogens of concern. In addition to USDA and FDA, many health-related organizations attest to the safety and effectiveness of food irradiation. A list of endorsers includes: the American Medical Association, American Dietetic Association, National Food Processors Association, American Meat Institute, World Health Organization, and the CODEX Alimentarius Commission.

FDA's 1990 approval for the use of irradiation as a food additive in poultry was in part based on the work of ARS researcher Dr. Donald Thayer. Thayer was the first to discover that E. coli O157:H7 could be controlled by irradiation. Later, he and other colleagues demonstrated that irradiation could control other major pathogens of concern such as Listeria, Salmonella, Campylobacter, and Bacillus cereus, on meat and poultry.

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Table 1: Severe Foodborne Illness, Annual Burden of Illness Estimates - Listeriosis

Attachment 3: Petition for Changes in Listeria monocytogenes regulatory program, Center for Science in the Public Interest, January 2000 [Available in PDF or Microsoft Word]

*Note: To read and print a PDF file, you must have the Adobe® Acrobat® Reader installed on your PC.

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