Evaluation of chemical decontamination treatments for beef trimmings against Escherichia coli O157:H7, non-O157 shiga toxin-producing, E. coli and antibiotic resistant and susceptible Salmonella Typhimurium and Salmonella Newport

The objective of the proposed study was to determine whether interventions known for reducing Escherichia coli O157:H7 contamination on beef trimmings were also effective against E. coli O157:H7, non-O157 STEC (O26, O45, O103, O111, O121, and O145), and parent and derived Salmonella Typhimurium and Salmonella Newport strains.

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Objective

The overall goal of the project was to determine whether interventions known for reducing Escherichia coli O157:H7 contamination on beef trimmings are also effective in reducing non-O157 Shiga toxin-producing E. coli (STEC), and multiple drug resistant (MDR) and susceptible Salmonella Newport and Salmonella Typhimurium.

Conclusions

Studies were conducted to evaluate the antimicrobial effects of chemical decontamination treatments against E. coli O157:H7, six non-O157 STEC serotypes (O26, O45, O103, O111, O121, and O145), and antibiotic susceptible and resistant (MDR and/or MDRAmpC) phenotypes of S. Newport and S. Typhimurium inoculated on beef trimmings; individual strains or mixtures were evaluated. The antimicrobial treatments evaluated were lactic acid (5%, at 25 or 55°C), acidified sodium chlorite (0.1%), peroxyacetic acid (0.02%), sodium metasilicate (4%), Bromitize® Plus (225 ppm active bromine), SYNTRx 3300 (pH 1.0), and AFTEC 3000 (pH 1.2). Findings indicated that the antimicrobial effects of these decontamination treatments against the non-O157 STEC serotypes and S. Newport/Typhimurium antibiotic resistance phenotypes were generally the same as those against E. coli O157:H7. Thus, decontamination interventions applied on beef trimmings against E. coli O157:H7 should be at least equally effective against strains of the top six CDC non-O157 STEC serotypes and susceptible as well as multidrug resistant S. Newport and S. Typhimurium.

Deliverable

The results of this project are submitted to the American Meat Institute Foundation as this final report. Additional deliverables will include technical scientific presentations (an overview of data was presented by John Sofos during his presentation on “The Science and Purpose of Laboratory Challenge Studies” at the symposium on “Validation of Enteric Pathogen Interventions: Scientific, Regulatory and Applied Approaches for Beef Slaughter and Further Processors” presented at the 98th Annual Meeting of the International Association for Food Protection, held in Milwaukee, WI (July 31-August 3, 2011), and peer-reviewed scientific papers as well as trade magazine articles. These deliverables will be available to industry and regulators as they develop interventions and policies for control of STEC other than E. coli O157:H7 and multidrug resistant Salmonella in beef trimmings.