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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Food Safety and Intervention Technologies Research » Research » Research Project #423481

Research Project: Shiga-Toxigenic Escherichia Coli (STEC) in the Beef Chain: Assessing and Mitigating the Risk by Translational Science, Education & Outreach

Location: Food Safety and Intervention Technologies Research

Project Number: 8072-41420-019-02-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Jan 1, 2012
End Date: Jun 30, 2019

To substantially mitigate the risk of STEC infections associated with beef products through comprehensive research, outreach and education. Develop and validate traditional and novel interventions to mitigate the risk of STEC contamination on hides, carcasses, ground beef and non-intact beef products. Amendment for the addition of $102,721: Funding will further support the current stated objectives. As well as: (Detection): i. Use reagents and assays developed by and/or adapted for STEC CAP to recover STEC-7, that being strains comprising serotypes O26, O111, O103, O121, O45, O145, and O157 of Shiga toxin-producing E. coli, from raw and non-intact veal and beef samples purchased at retail establishments in the mid-Atlantic region of the United States. a. The specific objectives are to: 1) determine the prevalence of the regulated serotypes of STEC (i.e., E. coli O157:H7 and “The Big Six”) in retail ground/non-intact veal and beef collected from Maryland, Delaware, Pennsylvania, and Virginia; 2) determine the presence of virulence genes (stx1, stx2, eae, ehxA, and others to be determined) and establish relatedness of isolates via molecular subtyping methods, and 3) share meat samples, enrichment broths, and isolates with STEC CAP collaborators for further testing. (Risk Analysis/Assessment): i. Create beef product pathway probabilistic microbial quantitative risk assessment (QRA) models for STEC-8 from live cattle to consumption to evaluate risk mitigation strategies and their expected public health impacts. ii. Validate QRA and risk-based corrective actions via STEC-8 inoculated studies.

The fundamental question being addressed by the proposed research is does non-intact beef pose a greater risk to public health than otherwise similar, but intact, cuts of beef. To this end, we will comparatively/directly evaluate the extent to which enhancement methods currently used by industry, namely blade tenderization, chemical enhancement, and vacuum tumbling, transfer pathogenic E. coli into the deeper tissues of the meat. We will also quantify if prior chemical treatment of subprimals or inclusion of an antimicrobial within the brine formulation used for injection and/or the marinade for vacuum tumbling will lessen the load of E. coli available for translocation and/or result in greater inactivation of the pathogen during subsequent storage or cooking. In addition to validating the effect of cooking on thermal inactivation of internalized Shiga toxin producing E. coli within enhanced steaks, we will also validate conditions needed for sonication of contaminated tenderization blades to remove/kill the pathogens. It should be noted that the experimental techniques to be used are quite effective and have already been peer-reviewed and published.