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

Office of Policy, Program Development and Evaluation

Meat and Poultry Advisory Committee Staff

White Paper on Escherichia coli O157:H7
Food Safety and Inspection Service
U.S. Department of Agriculture

November 1999

Summary

The Food Safety and Inspection Service (FSIS) is exploring whether further changes are needed in its policy regarding E. coli O157:H7 in light of new information that is emerging about the pathogen and its relation to human health. This paper presents background information on FSIS’ current policy regarding E. coli O157:H7 and discusses new information and developments that will likely have a bearing on the Agency’s policy. FSIS will re-evaluate its policy on E. coli O157:H7 through an open, participatory process, soliciting input from all of its various constituents. FSIS plans to hold a public meeting in the near future on this issue, but a date has not yet been selected.

In 1994, FSIS declared that E. coli O157:H7 is an adulterant in ground beef and instituted a testing program for the pathogen. FSIS established an end-product sampling program for ground beef to keep contaminated product from reaching consumers and to spur industry to institute pathogen reduction and HACCP-associated verification programs to reduce the risk of this pathogen in beef products. The Agency’s policy, as reflected in the attached FSIS Directive 10,010.1, dated February 1, 1998, was shaped in five major ways.

First, because E. coli O157:H7 was an emerging pathogen and not very well understood, the Agency was forced to design its policy based largely on the limited data available at the time. The fact that the pathogen produces severe and sometimes fatal consequences at what was believed to be a very low infectious dose (fewer than 10 organisms) spurred FSIS to take quick action.

Second, the pathogen was difficult to find in meat products. The lack of information about the pathogen made it difficult to determine whether the low rate at which it was found was attributable to the rarity of the pathogen, or to the fact that the method for detecting it was not very sensitive. Because the pathogen was found at a low rate, it has generally not been considered a hazard "reasonably likely to occur" and thus establishments have not considered it necessary to address it in their HACCP plans.

Third, the fact that the pathogen was difficult to find had an impact on the design of FSIS’ testing program. Because FSIS could not have confidence in a single negative result, once a positive is found by the Agency from a plant that grinds meat, there must be 15 consecutive negative findings from daily sampling before FSIS returns the plant to routine testing. Moreover, once such a plant has a positive finding, FSIS inspection personnel are instructed to select a sample if the positive finding occurred within the preceding six months--regardless of whether the plant has its own routine sampling program. Furthermore, sampling is conducted at retail locations that grind meat as well as at plants that do so. Sampling at retail, the point in the distribution chain closest to the consumer, provides an additional opportunity to intercept adulterated product.

Fourth, the fact that outbreaks attributed to E. coli O157:H7 were associated with ground beef led FSIS to focus its regulatory program on comminuted (ground) products. The first case control study for E. coli O157:H7 implicated ground beef as the risk factor most significantly associated with illnesses. The focus on ground product made sense because grinding moves the pathogen away from the surface of the product to the inside, so thorough cooking is needed to kill the pathogen. Americans were not used to cooking their ground beef patties, including hamburgers, thoroughly, and ground beef is extremely popular among young children who are affected most severely by the pathogen. These facts were used to make the initial decision in 1994 that E. coli O157:H7 adulterates ground beef as well as the decision in January 1999 that the presence of E. coli O157:H7 would adulterate not just ground beef, but any non-intact product or intact product intended for use as a non-intact product (Docket No. 97-068N, 64 Fed. Reg. 2803, January 19, 1999).

Fifth, cooking product found to be contaminated with E. coli O157:H7 was the only intervention known to FSIS at the time. That is why FSIS’ consistent advice has been that when this pathogen is found in non-intact meat or intact meat intended for non-intact use, the meat must be diverted for cooking under the control of FSIS.

Several major developments that will greatly enhance FSIS’ knowledge and understanding of E. coli O157:H7 are now in the offing and are likely to have a bearing on the Agency’s policy.

First, new information is emerging suggesting that E. coli O157:H7 is not as rare as previously thought. This new information comes from several sources.

In September 1999, FSIS began using a method for analyzing samples of products for E. coli O157:H7 that is four times more sensitive than the previous method. As a result of the new method, 40 percent (21 out of 53) of the positive samples found since the testing program began in 1994 have been found since the new test was initiated. This suggests that the low rate of positive findings may have had more to do with the sensitivity of the method being used than with the rarity of the pathogen.

Further evidence that E. coli O157:H7 may occur more frequently than was thought to be the case is provided by recent estimates of foodborne illness released by the Centers for Disease Control and Prevention (CDC). Those data show a much higher rate of illness from E. coli O157:H7 than had been previously reported by CDC, due mainly to milder cases of illness revealed by surveillance data. [Mead, Paul S., et al., "Food-Related Illness and Death in the United States," Journal of Emerging Infectious Diseases, Vol. 5, No. 5, 1999]. While not all of these illnesses are attributable to beef, they do support the observation that this pathogen occurs more frequently than was previously thought, and that the great majority of cases are limited to relatively mild symptoms that are unlikely to result in an infected person seeking medical care or to be reported to public health officials.

In addition to these data, the American Meat Institute is conducting a study in slaughter plants that should provide further insight into whether E. coli O157:H7 is a rare pathogen; particularly, whether it occurs on hides and freshly slaughtered carcasses of beef with some regularity. Under its protocol, 1 in 300 carcasses are tested for E. coli O157:H7 before hide removal, after hide removal, and after pathogen reduction interventions have been applied. The protocol was to run for 30 days, starting in early September. Twelve plants are involved in the protocol, although the specific plants involved have not been identified to FSIS. It is FSIS’ understanding that most of the testing is complete, and that the data are being analyzed. FSIS expects to receive the results of the testing by the end of November 1999.

The Agriculture Research Service, in Clay Center, Nebraska, also is carrying out research related to prevalence, and FSIS itself plans to conduct some sampling to assess the feasibility of identifying E. coli O157:H7 on carcasses and of establishing a routine, Agency-directed sampling program to supplement or replace FSIS' ongoing ground beef testing.

Second, a soon-to-be completed FSIS risk assessment for E. coli O157:H7 in ground beef and trimmings will better enable both the Agency and industry to identify interventions that can lead to public health improvements and weigh available options. FSIS has based this risk assessment on a comprehensive review of the available literature and data (see 63 Fed. Reg. 44232, August 18, 1998). Although needed peer reviews make it unlikely that the risk assessment will be completed before spring 2000, FSIS is planning to make a presentation on the risk assessment to the National Advisory Committee on Microbiological Criteria for Foods in December 1999. At that time, the risk assessment team from FSIS' Office of Public Health and Science will seek the Committee’s support for the assessment’s format and design. When the risk assessment on ground beef and trimmings is complete, FSIS expects to expand it to cover all meat products, as well as other products that may be affected by E. coli O157:H7.

Third, FSIS has received new information that could affect the scope of products affected by its policy. Specifically, FSIS has received data and information on blade tenderized roasts and steaks. As stated above, FSIS' policy is that non-intact cuts of meat are adulterated if contaminated by E. coli O157:H7. During a March 1999 public meeting on the Agency's E. coli O157:H7 policy, preliminary findings of research being done at Kansas State University on blade tenderized beef steaks were presented to the Agency. The researchers stated that the blade tenderization process transfers approximately 3-4 percent of surface contamination to the interior of the muscle. The researchers pointed out that proper cooking to a specified time/temperature combination resulting in rare steaks could reliably result in safe product. Industry members have further stated that muscle systems from which steaks are derived could be removed from larger primal or sub-primal cuts hygienically. The beef industry has been persistent in encouraging FSIS to exempt blade tenderized product, especially when derived hygienically or with reduced possibilities for becoming contaminated, from the scope of the E. coli O157:H7 policy.

As of fall 1999, FSIS has tentatively determined that there is insufficient information regarding the hygienic processing of muscle systems to narrow the scope of products affected by the E. coli O157:H7 policy. FSIS expects its planned effort to broaden the risk assessment will address some of the issues raised by the industry. Meanwhile, FSIS has encouraged industry to label their intact and non-intact primal and sub-primal cuts with appropriate cooking statements. The 1999 Food Code (section 3-401.11) prescribes appropriate cooking instructions for intact versus non-intact steaks for destruction of organisms of public health concern.

Fourth, there may be interventions other than cooking product under FSIS control that could be used to address a positive E. coli O157:H7 finding. For example, irradiation offers the possibility of treating raw meat products to eliminate E. coli O157:H7. In addition, FSIS is willing to consider whether other alternatives to cooking product within an FSIS-inspected establishment could be used to address a positive finding.

Several other considerations are likely to be important as the Agency reviews its policy on E. coli O157:H7. For example, the fact that on January 25, 2000, all meat and poultry plants will be operating under the Pathogen Reduction and HACCP rule will have a positive impact on food safety and may affect the Agency’s approach to the regulation of E. coli O157:H7. In addition, actions taken by the meat industry to reduce the pathogen at the production level also would be considered by FSIS in reviewing its policy.

These new developments could have a significant impact on FSIS’ policy on E. coli O157:H7. Following are some areas for consideration.

1. If FSIS finds that E. coli O157:H7 occurs with some regularity on hides and carcasses of feedlot cattle but not on cattle raised under different production practices, should the pathogen be considered a hazard "reasonably likely to occur" only in slaughter and processing operations that use feedlot cattle, and thus be addressed in their HACCP plans?
2. Should FSIS re-design its testing program? Specifically:

• Are any changes needed in the proportion of samples taken in-plant and at retail?

• Should FSIS alter its policy that 15 consecutive samples be negative after a positive finding?

• Should FSIS continue selecting a sample if a plant has a positive finding within the last 6 months, or should the Agency defer to plant routine testing completely and remove the 6-month restriction? If FSIS sampling is continued under these circumstances, should the rules for the random selection of samples be changed?

• Should FSIS sampling of carcasses replace or supplement ground beef sampling at slaughter plants?

1. Should FSIS consider a plant's generic E. coli and Salmonella results in making its decision on whether to target a plant’s products for sampling?
2. What effect should a plant’s testing or verification program have on whether and how FSIS targets its testing in that plant?
3. How should FSIS treat non-intact product? Specifically, should blade-tenderized beef steaks and roasts--with specific cooking instructions for destroying the pathogen and handling instructions for preventing cross-contamination and temperature abuse-- be treated the same as other non-intact beef with regard to the FSIS policy?
4. How effective are voluntary producer actions in providing animals with reduced levels of E. coli O157:H7 to plants, and should these voluntary activities, if effective, affect slaughter plants' strategies and FSIS’ policy?

FSIS anticipates a number of developments in the coming months that will have a significant bearing on its policy on E. coli O157:H7. It is FSIS' intent to be guided in its policy development process by the best available science and to reevaluate its policy through an open, participatory process. FSIS will be soliciting input on these and other questions at its upcoming public meeting on E. coli O157:H7.

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Last modified:  November 25, 2002