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1. Determine efficacy of current beef processing antimicrobial interventions in reducing
MDR Salmonella levels on beef carcasses. <P>
2. Determine efficacy of current beef processing antimicrobial interventions in reducing
non-MDR Salmonella levels on beef carcasses. <P>
3. Compare effects of antimicrobial interventions on MDR Salmonella with the effects on
non-MDR Salmonella. <P>
4. As stated in the interim report E. coli O157:H7 strains, both human disease-associated and
non-human disease-associated, were added to the experiment.
Findings: The objective of this project was to determine if Holstein steers pose a serious risk for introduction into the fed beef population of Salmonella that are resistant to multiple antibiotics. This group of Salmonella is referred to as multi-drug resistant (MDR). MDR Salmonella has been associated with dairy production. It is believed that dairy cattle are responsible for the higher level of MDR Salmonella seen in samples obtained from cull beef plants as compared to those obtained from fed beef packing plants. If Holstein steers are exposed to MDR Salmonella during the neonatal period (i.e., while at the dairy) or during the growing phase, Holstein (dairy) steers may pose a risk for introduction of MDR Salmonella into the fed beef complex. Yet, the prevalence and level of MDR Salmonella for Holstein steers is not known. This information will serve as the basis for developing strategies to prevent contamination of beef products with MDR Salmonella. Based on the preliminary data, Holstein steers do not carry Salmonella at a higher rate than other fed cattle (0.5% vs. 3.2%). More isolates will be collected then MDR status will be determined.