The stated objectives for this work were:
<ol><li>Determine the prevalence of E. coli O157:H7 and Salmonella and the level of generic microbial contamination on the hides of slaughter cows and bulls.</li>
<li>Determine the prevalence of E. coli O157:H7 and Salmonella and the level of generic microbial contamination on cow/bull carcasses before pre-evisceration microbial interventions.</li>
<li>Determine the prevalence of E. coli O157:H7 and Salmonella and the level of generic microbial contamination on cow/bull carcasses after all microbial interventions.</li>
<li>Determine the relationship between the prevalence of E. coli O157:H7 and the prevalence of Salmonella and measures of the level of generic microorganisms for cow/bull hides and carcasses.</li></ol>
<p>Outbreaks of foodborne illness linked to consumption of hamburger contaminated with E. coli O157:H7 have had a devastating effect on profitability of the beef industry. We have established that the prevalence of E. coli O157:H7 on the hides of fed cattle is high, that often pre-evisceration carcasses become contaminated with E. coli O157:H7, and that microbial interventions result in most (97%) fed-beef carcasses being negative for E. coli O157:H7. Yet little is known about the prevalence of E. coli O157:H7 on the hides and carcasses of cull cows and bulls. Thus, the experiments described here establish the prevalence of E. coli O157:H7 and Salmonella on the hides and carcasses of cull cows and bulls and evaluate the relationship between the prevalence of E. coli O157:H7 and other measures of microbial contamination including the prevalence of Salmonella and levels of other generic bacteria.</p>