FIG. 1.

Examination of coincident contamination with Salmonella and E. coli O157:H7 on cattle hides and carcasses at slaughter. A total of 380 hide and carcass samples were collected from each of four plants in the winter and spring (95 samples each day; 2 days each season). The samples were evaluated for the presence of each pathogen using both the enrichment and the enumeration techniques described, and the results were scored using the definitions described in Materials and Methods. The samples were binned according to the outcome, and the geometric mean and percentage of samples in each bin were then calculated. The circles represent the percentages of cattle hide and carcass samples at each plant that were found to contain neither (indicated by white circles), either (indicated by gray circles), or both (indicated by black circles) Salmonella and E. coli O157:H7, and the geometric mean pathogen load is indicated by the position in the plot of E. coli O157:H7 CFU/100 cm² versus Salmonella CFU/100 cm². Ec., E. coli; Sal, Salmonella; neg, negative.