The Effect of Lactic Acid and Cooking on the Survivability of E. coli O157:H7 in Needle Tenderized Beef Steaks Managed Under Simulated Industry Conditions

E. coli O157:H7 used to only be of concern with ground beef, recently the concern has
changed to any meat that has been tenderized or injected, as was found in the case with
tenderized frozen steaks that were sold to consumers. On August 20, 2004, approximately
406,000 pounds of frozen beef products were recalled due to E. coli O157:H7 contamination
(FSIS-USDA, 2004). On May 11, 2007 another recall occurred. The items included: strip loins
steaks, ball tip steaks, top butt steaks, and sirloin steaks (FSIS-USDA, 2007). All of these steaks
were mechanically tenderized and linked to illnesses resulting from E. coli O157:H7. These two
outbreaks document that E. coli O157:H7 can be transferred into the steaks when they are
mechanically tenderized. Because of this, the U.S. Food Safety Inspection Service (FSIS)
currently recommends that mechanically tenderized steaks be cooked to a minimum of 68.3
o
C
for 15 seconds to ensure that E. coli O157:H7 bacteria cells have been killed (FSIS-USDA,
2007). Therefore; it is important to document that cooking to 68.3
o
C for 15 seconds is sufficient
to kill E. coli O157:H7 cells in mechanically tenderized products.
<P> Lactic acid is used as an antimicrobial to control or reduce bacterial contamination. One
bacterium that lactic acid helps to control is E. coli O157:H7. Lactic acid was first discovered by
Swedish chemist Carl Wilhelm Scheele in 1789 while investigating the souring of burgundy
wine (Benninga, 1990). Since then scientist have found that lactic acid helps in controlling
different bacteria. Most facilities use lactic acid as a critical control point (CCP) in their HACCP
plans. <P>

The objective of this research was to characterize the effects of lactic acid spray on
needle-tenderized beef strip loins inoculated with low and high levels of Escherichia coli
O157:H7 prior to cooking to various endpoint temperatures.