Efficacy of commonly used antimicrobial interventions on Shiga toxin-producing Escherichia coli serotypes O45, O121, and non-MDR and MDR Salmonella inoculated fresh beef

The overall objective is to validate effectiveness of antimicrobial compound treatments on inactivation of STEC and Salmonella (MDR versus non-MDR strains) inoculated fresh beef. AMIF recently funded ARS to conduct a similar study on the following non-O157 STEC: O26, O103, O111, and O145. This study completed the work by adding the other two non-O157 STEC from the CDC’s top six and include MDR and non-MDR Salmonella Typhimurium and Newport.

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Objectives

The overall objective was to determine effectiveness of antimicrobial compound treatments currently used in meat industry on inactivation of STEC and Salmonella on inoculated fresh beef.

Conclusions

Although numerous interventions targeting E. coli O157:H7have been developed and implemented to decontaminate meat and meat products during the harvesting process, the information on efficacy of these interventions against non-O157 STECs and Salmonella, especially MDR strains versus non-MDR strains, is limited. A study was conducted to determine whether antimicrobial compounds currently used by the meat industry are effective against non-O157 STEC serogroups O45 and O121 compared to E. coli O157:H7 and against non-MDR and MDR Salmonella. All antimicrobial compounds that we tested were effective against non-O157 STEC and Salmonella.The reductions of these pathogens on inoculated fresh beef with tested compounds were at least as great as against E. coli O157:H7. The degree of effectiveness depended on the antimicrobial compounds used. In the present study, lactic acid, hot water, and acidified sodium chlorite were most effective in reducing the target pathogens. FreshFx had an intermediate effect in reducing pathogens, while peroxyacetic acid and BoviBrom had the least effect. The effectiveness of these compounds on non-MDR and MDR Salmonella was inconclusive, but Typhimurium were more resistant than Newport.

Deliverable

The results will assist the meat industry in identifying antimicrobial compounds suitable for controlling these pathogens in addition to E. coli O157:H7 and, thus, enhancing meat safety.