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Survey of the Prevalence of Escherichia coli O157:H7 on the Surface of Subprimal Cuts of Beef During Summer Months (Phase II)

Kennedy, Ken
ABC Research
Start date
End date
The Food Safety Inspection Service of the U.S. Department of Agriculture (FSIS-USDA) defines non-intact beef products as ground beef; beef injected with solution; beef that has been mechanically tenderized by needling, cubing, frenching or pounding devices, and beef that has been reconstructed into formed entrees (FSIS-USDA, 1999). The use of techniques such as needle or blade tenderization, and enhancement by injecting subprimals with a brine or marinade solution, has become a common means of improving quality attributes of beef products. Whole muscle cuts (e.g. chucks, ribs, tenderloins, strip loins, top sirloin butts, rounds) may be treated with these technologies to increase tenderness or to add ingredients for quality purposes. The treatments often occur before fabrication into steaks and may include solid needle or hollowneedle tenderizing, in which a solution is pumped into the whole muscle. In the latter case, the solution typically is recirculated, refrigerated and may be treated to ensure quality.

Non-intact products are considered by FSIS to be high-risk due to the potential internalization of pathogens via the mechanical tenderization process. Consumers perceive non-intact beef products to be whole muscle cuts, and subsequently may not cook them to a sufficient internal temperature to destroy harmful bacteria. In 1999, the Food Safety Inspection Service (FSIS) published a notice stating its intention to include non-intact beef products in the Escherichia coli O157:H7 testing program. As the use of tenderization techniques becomes more common as a means of improving beef quality, it is important to understand the implications for beef safety.

The objective of this study was to determine the prevalence of E. coli O157:H7 and indicator microorganisms on the surface of beef subprimals prior to mechanical tenderization or moisture enhancement.

More information
Findings: These results indicate that the incidence of E. coli O157:H7 contamination on the surface of beef sub-primal cuts intended for mechanical tenderization (enhancement) was very low (i.e., <0.17%) with no E. coli O157:H7 being detected in any of the 599 sub-primal samples collected from August through November of 2004. A previous study (NCBA Project Report, March 25, 2004) likewise found none of 600 samples of the same beef sub-primal cuts positive for E. coli O157:H7 during January and February of 2004. Thus no E. coli O157:H7 was detected on any of the 1,199 sub-primal samples tested in both phases of this project and the resulting overall incidence of E. coli O157:H7 contamination beef sub-primal cuts intended for enhancement was less than 0.083%.

A previous study (NCBA Project Report, 2003) demonstrated an extremely low internalization rate of surface contaminating E. coli O157:H7 into subprimals by blade tenderization. These results along with those of the previous prevalence study and the internalization study indicate that internal contamination of beef sub-primal cuts with E. coli O157:H7 via mechanical tenderization (enhancement) is a very improbable event.

For complete projects details, view the Project Summary.

Funding Source
Nat'l. Cattlemen's Beef Assoc.
Project number
Escherichia coli
Natural Toxins
Viruses and Prions
Bacterial Pathogens
Chemical Contaminants
Meat, Poultry, Game