Antimicrobial interventions for O157:H7 and non-O157 shiga toxin-producing escherichia coli on beef subprimal and mechanically tenderized steaks

Abstract

Non-O157 Shiga toxin-producing Escherichia coli (STEC) is an emerging risk for food safety. Although numerous postharvest antimicrobial interventions have been effectively used to control E. coli O157:H7 during beef harvesting, research regarding their effectiveness against non-O157 STEC is scarce. The objectives of this study were (i) to evaluate effects of the spray treatments-ambient water, 5% lactic acid (LA), 200 ppm of hypobromous acid (HA), and 200 ppm of peroxyacetic acid (PA)-on the reduction of O157:H7 or non-O157 STEC (O26, O103, O111, and O145) with high (106 log CFU/50 cm2) or low (102 log CFU/50 cm2) levels on beef subprimals after vacuum storage for 14 days and (ii) to evaluate the association of the antimicrobial treatments and cooking (50 or 70°C) on the red°Ction of the pathogens in blade-tenderized steaks. The treatment effects were only observed (P ∼ 0.012) on samples taken immediately after spray intervention treatment following inoculation with a high level of O157:H7. The LA and PA treatments significantly red°Ced low-inoculated non-O157 STEC after spray intervention; further, the LA and HA treatments resulted in significant red°Ctions of non-O157 STEC on the low-inoculated samples after storage. Although cooking effectively red°Ced the detection of pathogens in internal steak samples, internalized E. coli O157:H7 and non-O157 STEC were able to survive in steaks cooked to a medium degree of doneness (70°C). This study indicated that the red°Ction on surface populations was not sufficient enough to eliminate the pathogen's detection following vacuum storage, mechanical tenderization, and cooking. Nevertheless, the findings of this study emphasize the necessity for a multihurdle approach and further investigations of factors that may influence thermal tolerance of internalized pathogenic STEC.