The Committee was asked to answer several questions with regard to Escherichia coli O157:H7 in Blade-tenderized, non-intact beef.  A subcommittee charged with this task met on August 3, 2001 and January 23, 2002 in Washington, DC and discussed the FSIS questions to NACMCF regarding E. coli O157:H7 in blade-tenderized, non-intact beef.   The subcommittee reviewed a Masters Thesis entitled “Escherichia coli O157:H7 Risk Assessment for Production and Cooking of Blade Tenderized Beef Steaks (Sporing, 1999).  A presentation was also given by a representative from Kansas State University entitled "Evaluation of Pathogen Risks Associated with Blade Tenderized Beef Cooked to Varying Degrees of Doneness." 

"QUESTION #1 - Is the available information on non-intact products adequate to answer questions 2 and 3?  If not, are there other reasons to conclude that the translocation of E. coli O157:H7 that occurs with the blade tenderization or similar processes renders traditional cooking (consider the traditional cooking process for these products to be very rare or rare) of these products inadequate to kill the pathogen?"

 The Committee concluded that there was sufficient data to answer Question #2 however, there was insufficient data to answer Question #3.   Research needs were identified and are listed at the end of the document.

The Committee felt there was a paucity of epidemiologic data in relation to illness linked with blade tenderized steaks.

Cases of human illness due to E. coli O157:H7 are reported to the Centers for Disease Control and Prevention (CDC) following investigation by state and local public health officials in individual states.  While all states report basic demographic and clinical data for cases, the states vary in the extent to which an additional investigation is undertaken to identify risk factors for, and sources of, infection.  Cases are classified as sporadic or outbreak-associated; not all outbreaks have an identified source or vehicle.

Standardized forms provided by CDC and used at the state and local level for case investigation do not include questions on consumption of steak or roast, specifically.  Therefore, surveillance data reported by states to CDC on sporadic E. coli O157:H7 infection does not contain specific information on the proportion of cases associated with steaks or roasts, either intact or non-intact.

Among reported illnesses of E. coli O157:H7 with an identified source, there are two incidents associated with steaks (Canada and Michigan), one with roasts in Canada and one associated with roast beef (Wisconsin)¹.  In the Michigan outbreak (two individuals with illness), blade-tenderized beef steak was identified as the most likely vehicle of infection.  In the Canadian incidents, two sporadic cases were associated with consumption of roast beef or Tournedos.  There was no further investigation of the Canadian beef products to the point of distinguishing whether it was intact or blade-tenderized.

The case control studies of sporadic E. coli O157:H7 infection have been carried out through CDC.  Although questions on consumption of beef, and the extent to which it was cooked (example  - rare, pink, well done, etc.) were included, characterization of steaks or roasts as intact vs blade-tenderized was not done.

Thus, the available evidence shows that steaks and roasts can transmit E. coli O157:H7 infection, but does not allow discrimination for the relative contribution of commodity type to transmission.

 "QUESTION #2 - Do non-intact, blade tenderized beef steaks present a greater risk to consumers from E. coli O157:H7 compared to intact beef steaks if prepared similarly to intact beef steaks?"

 The following statements are based on scientific data contained in the Masters Thesis mentioned above.

Following inoculation of the surface of intact beef steaks (½”, 3/4” or 1 ¼” in thickness) with a five-strain cocktail of E. coli O157:H7 to approximately 10⁷ cfu/cm², single-pass blade-tenderization processing resulted in internalization of approximately 3 x10³ cfu/gm or approximately 3-4% of the initial inoculum.  Thus, the potential for an infective dose of E. coli O157:H7 to be contained in the interior of blade-tenderized beef exists.

This presents a concern/risk for blade-tenderized beef steaks being served very rare with cold spots (less than 120 F internal temperature), particularly to immunocompromised individuals. 

Non-intact, blade tenderized beef steaks do not present a greater risk to consumers if the meat is oven broiled and cooked to an internal temperature of 140 F or above.

Although data were more variable at temperatures below 140 F, it was still possible to achieve a 3.2 log reduction for blade tenderized and a 5.2 log reduction for intact beef steaks at 120 F based on cross-sectional samples of inoculated steaks

 There is also a lack of data for the proportion and quantity of blade-tenderized beef produced in the U.S. as well as to whom it is distributed - retail, foodservice, etc.

 The cooking instructions provided to industry and consumers should be the same, unless an alternative equivalent industry process can be validated.

QUESTION #3 - Do non-intact, blade tenderized beef roasts present a greater risk to consumers from E. coli O157:H7 compared to intact beef roasts if prepared similarly to intact beef roasts?

The Committee concluded that there are insufficient data to adequately answer this question.

Question #4 – Does the available scientific evidence support the need for a labeling requirement to distinguish between intact and non-intact products in order to enhance public health protection?

The Committee concluded that there was insufficient data to warrant a response at this time.  Research needs were identified and are listed at the end of this document.

RESEARCH NEEDS

The following research needs are identified in order to obtain more information about the microbiological profile, cooking practices, industry practices for blade tenderizing, and the proportion of blade tenderized beef marketed in the U.S.

1. A lack of quantitative (variable) baseline data for E. coli O157:H7, or appropriate indicator organisms such as E. coli biotype 1, coliforms, and/or Salmonella, on primal and subprimal cuts of beef immediately prior to blade tenderization was identified.  Data should be collected from very small and large establishments to determine if there are any differences.

2. Survival of E. coli O157:H7 in core beef samples following cooking to specified temperatures. 

3. Industry and consumer practices for cooking; such as grill vs oven.

4. Industry practices for blade tenderization; such as the type of machine, number of passes through the tenderizer, sanitation of equipment, through put, temperature of the processing room, and the temperature of the primal cuts.

5. Proportion and quantity of blade-tenderized beef distributed to retail and food serviceestablishments.

6. Better understanding of the heat and mass transfer characteristics of blade-tenderized meats cooked by various means.

7. Quantify the D and z values of the individual strains of E. coli O157:H7 used in the Sporing (1999) study.  Individual strains should be identified and characterized.

Additional data are being presented on January 24, 2002 at the National Cattleman’s Beef Association meeting in Denver, CO that may prove helpful in answering the questions posed to NACMCF.

Recommendations to FSIS:

1. FSIS should consider requesting NACMCF develop guidelines for validating the processes for blade tenderizing and cooking beef steaks and roasts.

2. FSIS should assemble/collect data in order for NACMCF to determine if pathogens other than E. coli O157:H7, such as Salmonella spp. and Clostridium perfringens pose a risk in blade tenderized beef roasts.

3. FSIS should request additional studies be undertaken to reflect the research needs and follow developed guidelines as stated in Recommendation #1.

4. If an outbreak or sporadic case of illness is attributed to the consumption of beef steak, CDC, in cooperation with FSIS, should request that state and local health departments include the following questions during the investigation:
1. How was the steak cooked?
2. Where was the steak purchased?
3. How was the steak processed at the restaurant or retail establishment and manufacturing facility (e.g. blade tenderized, marinated)?

References:

1. Rodrigue, D.C., E.E. Mast, K.D. Green, J.P. Davis, M.A. Hutchison, J. Wells, T.J. Barrett, and P.M. Griffin.  1995.  A university outbreak of Escherichia coli O157:H7 infections associated with roast beef and an unusually benign clinical course.  J. Infect. Dis. 172 (4): 1122-1125.