Survivability of Escherichia coli O157:H7 in mechanically tenderized beef steaks subjected to lactic acid application and cooking under simulated industry conditions

C. C. Chancey, J. C. Brooks, J. N. Martin, A. Echeverry, S. P. Jackson, L. D. Thompson, M. M. Brashears

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Mechanical tenderization improves the palatability of beef; however, it increases the risk of translocating pathogenic bacteria to the interior of beef cuts. This study investigated the efficacies of lactic acid spray (LA; 5%), storage, and cooking on the survivability of Escherichia coli O157:H7 in mechanically tenderized beef steaks managed under simulated industry conditions. Beef subprimals inoculated with either high (105 CFU/ml) or low (103 CFU/ml) levels of E. coli O157:H7 were treated (LA or control) and stored for 21 days prior to mechanical tenderization, steak portioning (2.54 cm), and additional storage for 7 days. Steaks were then cooked to an internal temperature of 55, 60, 65, 70, or 75°C. Samples were enumerated and analyzed using DNA-based methods. Treatment with LA immediately reduced E. coli O157:H7 on the lean and fat surfaces of high- and lowinoculum- treated subprimals by more than 1.0 log CFU/cm2 (P < 0.05). Storage for 21 days reduced surface populations of E. coli O157:H7 regardless of the inoculation level; however, the populations on LA- and control-treated lean surfaces of high- and low-inoculum-treated subprimals were not different after 21 days (P > 0.05). E. coli O157:H7 was detected in core samples from high-inoculum-treated steaks cooked to 55, 60, or 70°C. Conversely, E. coli O157:H7 was not detected in core samples from low-inoculum-treated steaks, regardless of the internal cooking temperature. These data suggest that LA- and storage-mediated reduction of pathogens on subprimals exposed to typical industry contamination levels (101 CFU/cm2) reduces the risk of pathogen translocation and subsequent survival after cooking.

Original languageEnglish
Pages (from-to)1778-1783
Number of pages6
JournalJournal of food protection
Volume76
Issue number10
DOIs
StatePublished - Oct 2013

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