|Food Safety and Inspection
United States Department of Agriculture
Washington, D.C. 20250-3700
Resources/Contact Information Revised May 2000
The Food Safety and Inspection Service (FSIS) has announced its action plan for addressing Listeria monocytogenes in response to a nationwide outbreak of listeriosis associated with ready-to-eat meat and poultry products in late 1998 and early 1999 and a spate of recalls related to the pathogen. The action plan contains both near-term and long-term initiatives.
FSIS has announced three near-term initiatives. First, FSIS is scheduled to publish in the May 26 Federal Register a notice advising establishments to reassess their Hazard Analysis and Critical Control Point (HACCP) plans to ensure they are adequately addressing L. monocytogenes. Second, FSIS is providing guidance to the industry on practices that have been used successfully by other meat and poultry establishments to prevent the occurrence of L. monocytogenes in ready-to-eat products. Third, FSIS is carrying out educational efforts targeted to those individuals who are at an increased risk of developing listeriosis.
FSIS also announced four long-term initiatives. First, FSIS is drafting a protocol to study the post-production growth of L. monocytogenes in a wide variety of ready-to-eat products and will ask USDA's Agricultural Research Service to conduct the study. Second, FSIS is developing an in-depth verification protocol that can be used to evaluate whether plants producing ready-to-eat products have reassessed their HACCP plans to adequately address L. monocytogenes. Third, FSIS is working with the Food and Drug Administration (FDA) to conduct a risk assessment for L. monocytogenes. And fourth, FSIS is developing performance standards for ready-to-eat products that will address the need to control all pathogens, including L. monocytogenes, in these products.
L. monocytogenes is found in soil and water and can contaminate a variety of raw foods, such as uncooked meats and vegetables. Foods can also become contaminated after processing; examples are soft cheeses, hot dogs, and luncheon meats. Consumption of food contaminated with L. monocytogenes can cause listeriosis, an uncommon but potentially fatal disease in newborns, the elderly, and persons with weakened immune systemssuch as those with chronic disease, HIV infection, or persons taking chemotherapy for cancer. Listeriosis also is a major concern in pregnant women. Even though symptoms may be relatively mild in the mother, the illness can be transmitted to the fetus, causing serious illness or fetal death.
During the late 1980's, L. monocytogenes emerged as a problem in deli meats and other processed products. FSIS and FDA worked with processing plants to improve their procedures and emphasized the "zero" tolerance (no detectable level permitted) for the pathogen in ready-to-eat products. Between 1989 and 1993, the rate of illness from L. monocytogenes declined 44 percent. Preliminary analysis of rates since 1993 has not shown any changes in rates of illness.
However, in the fall of 1998, an increased number of reported cases of illness due to a specific subtype of L. monocytogenes led State health departments and the Centers for Disease Control and Prevention (CDC) to investigate. CDC and State and local health departments identified the vehicle of transmission as hot dogs and possibly deli meats produced by one manufacturer under many brand names. On December 22, 1998, in response to reports of illness, the manufacturer voluntarily recalled specific production lots of these products that might be contaminated. Subsequently, CDC and FSIS investigators isolated the outbreak strain of L. monocytogenes from an opened and a previously unopened package of hot dogs manufactured by one plant. In addition, a different strain of the pathogen was isolated from unopened packages of deli meats produced at the same plant. CDC has reported 101 illnesses, 15 adult deaths, and 6 stillbirths or miscarriages associated with the "E" pattern subtype of L. monocytogenes.
The investigators used Pulse-Field Gel Electrophoresis (PFGE) testing to link products produced by the plant with the outbreak. PFGE technology, now being carried out in public health laboratories around the country, enables molecular subtyping, or fingerprinting, of pathogens isolated from both humans and foods. The ability to subtype pathogens is important because it helps public health agencies to identify a cluster of related illnesses and to link specific products to specific human illnesses when the "fingerprints" match.
Because of FSIS' concern about the nationwide outbreak of listeriosis associated with ready-to-eat meat and poultry products, the Agency held a public meeting on February 10, 1999, to gather information to develop a strategy for regulation, research, education, and enforcement to further reduce the risk of human illness.
FSIS has always had a zero tolerance (no detectable level permitted) for L. monocytogenes in ready-to-eat products such as hot dogs and luncheon meats, and the Agency began testing for the pathogen in 1987. Approximately 3,500 samples are analyzed for L. monocytogenes each year. The following product categories are included in the monitoring program: (1) beef jerky, (2) roast beef, cooked beef, and cooked corned beef, (3) sliced ham and luncheon meat, (4) small-diameter sausage, (5) large-diameter sausage, (6) cooked, uncured poultry, (7) salads and spreads, and (8) dry and semi-dry fermented sausage.
In calendar year 1998, out of 3,547 samples of ready-to-eat products analyzed through this monitoring program, 90 samples--or approximately 2.5 percent--tested positive for L. monocytogenes. Products targeted for L. monocytogenes testing by FSIS are generally held voluntarily by the plant until results are available so that potentially contaminated products do not reach consumers. However, in the event that FSIS discovers a positive sample and the product was not held by the plant, FSIS requests that the plant initiate a product recall. In addition, when a positive sample is found, FSIS conducts follow-up testing of products produced by the plant.
Federal Register Notice on Reassessing HACCP Plans. On May 26, 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 they are adequately addressing L. monocytogenes. Under HACCP, plants that produce ready-to-eat products must conduct a hazard analysis to determine the food safety hazards reasonably likely to occur in their production processes and to identify the preventive measures needed to control those hazards.
Because recent developments indicate that L. monocytogenes is a hazard reasonably likely to occur in ready-to-eat products, FSIS' regulations require that plants reassess their HACCP plans for those products. If this reassessment reveals that L. monocytogenes contamination is reasonably likely to occur in the plants production process, then the hazard must be addressed in a HACCP plan.
The Agency is basing its decision on the following evidence: (1) the recent outbreak of listeriosis, (2) findings of L. monocytogenes contamination in ready-to-eat products, and (3) other information now available on the prevalence and persistence of this foodborne pathogen.
In the 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. They 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.
Guidance to Industry. FSIS is providing guidance to the industry on practices that have been used successfully by other meat and poultry establishments to prevent the occurrence of L. monocytogenes in ready-to-eat products. The guidance was developed using the best scientific and technical information currently available from government, individual meat and poultry processing establishments, and trade associations. A number of trade associations have 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. To complement these materials, FSIS guidance materials focus on environmental and end-product testing.
Consumer Education. FSIS is carrying out educational efforts targeted to reach those individuals who are at an increased risk of developing listeriosis. People at risk include pregnant women, newborns, the elderly, and persons with weakened immune systemssuch as those with chronic disease, HIV infection, or persons taking chemotherapy for cancer.
People at risk for listeriosis, their family members, and individuals preparing food for them should:
Study on Post-Production Growth of Listeria. FSIS is drafting a protocol to study the post-production growth of L. monocytogenes in a wide variety of ready-to-eat products and is asking USDA's Agricultural Research Service to conduct the study. The study is designed to generate data on the growth of the pathogen in all categories of ready-to-eat products. In addition, the study will generate data on the molecular subtypes of Listeria pathogens found in these products, which may be useful in responding to future outbreaks of listeriosis.
In-Depth Verification Protocol. The Agency is developing an in-depth verification protocol that could be used to evaluate whether plants producing ready-to-eat products have reassessed their HACCP plans to adequately address L. monocytogenes. The protocol would be used by a technically qualified, multi-disciplinary team, which would visit the establishment, observe plant operations, and review relevant records, including the establishments HACCP plan. At the end of the review, the team would compile written findings and present them to FSIS management for further follow up with the plant and regulatory action, if necessary.
Risk Assessment. FSIS is working with FDA to conduct a risk assessment for L. monocytogenes that will focus on all foods, but in particular refrigerated, ready-to-eat foods. The risk assessment will examine a number of issues, including what foods are most likely to contain the pathogen, the number of organisms generally found on contaminated foods, how frequently foods are contaminated, whether some strains of the pathogen are more virulent than others, the extent of the pathogens growth during storage, and the health effects to "at risk" populations of consuming specific numbers of organisms. The risk assessment also will help to identify research needs and priorities and is expected to be completed in November 1999.
Performance Standards for Ready-to-Eat Products. FSIS is developing food safety performance standards for shelf-stable and perishable ready-to-eat products that will address the need to control all pathogens, including L. monocytogenes. The performance standards will establish a level of pathogen reduction that plants producing ready-to-eat products must meet during their operations in order to produce safe products but will allow the use of customized, plant-specific processing procedures other than those prescribed in earlier, command-and-control regulations. The performance standards will improve the safety of these products, provide plants with the flexibility to adopt innovative, science-based food safety processing procedures and controls, and provide objective, measurable standards that can be verified by FSIS.
For More Information
These materials are available on the FSIS web site: www.fsis.usda.gov
The following is available on the FDA web site: www.fda.gov under Dockets.
For Further Information Contact:
FSIS Congressional and Public Affairs Staff
Phone: (202) 720-3897
Fax: (202) 720-5704
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