<OL> <LI>Quantify the translocation (MFS) and distribution (FSIT) of E. coli O157:H7 and other non-verocytotoxigenic E. coli (STEC) in subprimal beef caused by mechanical and chemical methods of tenderization. Conduct prefatory study to determine the feasibility of measuring and modeling the cross contamination from one subprimal to the next during tenderization. <LI> Obtain kinetic growth data on E. coli O157:H7 in tenderized beef during storage at refrigerated and abuse temperatures. <LI>Develop a computer simulation model for systematic risk assessment.
Approach: 1. Post-rigor beef subprimals will be used in both mechanical and chemical tenderization studies. 2. Growth kinetics of E. coli in both mechanically/chemical-tenderized beef under different storage temperatures will be studied and models developed. 3. The cooking component of the proposed study will be conducted for both mechanically-tenderized and chemically-injected beef. 4. Blades/needles used for tenderization will be contaminated with high levels of the pathogen cocktails and stored at 4oC for up to 30 min to allow for attachment of the cells to the stainless steel surfaces.