TABLE 4.
Mean percent prevalence and load of E. coli O157:H7 on cull cattle hides and carcasses analyzed by season
| E. coli O157:H7 parameter | Valuea
|
P value | |||
|---|---|---|---|---|---|
| Summer | Fall | Winter | Spring | ||
| Hide | |||||
| Prevalence (%) (±SD) | 55.7 ± 22.6 | 38.7 ± 24.6 | 50.4 ± 37.8 | 43.2 ± 20.7 | 0.6107b |
| Load (CFU/100 cm2) | |||||
| Enumeration positive (%) (±SD) | 5.8 ± 7.2 | 0.4 ± 0.6 | 3.7 ± 6.4 | 1.5 ± 2.5 | 0.1626b |
| n | 44 | 3 | 28 | 11 | |
| Median | 80 | 80 | 40 | 40 | 0.1817c |
| Minimum | 40 | 40 | 40 | 40 | |
| Maximum | 9.8 × 103 | 80 | 7.2 × 102 | 1.0 × 103 | |
| Preevisceration carcass | |||||
| Prevalence (%) (±SD) | 18.3 ± 16.6 | 14.9 ± 13.6 | 19.5 ± 31.2 | 14.2 ± 13.2 | 0.9407b |
| Load (CFU/100 cm2)d | |||||
| Enumeration positive (%) (±SD) | ND | ND | 3.2 ± 7.1 | 1.6 ± 2.5 | 0.5615e |
| n | ND | ND | 24 | 12 | |
| Median | ND | ND | 1.6A | 0.8B | 0.0082f |
| Minimum | ND | ND | 0.8 | 0.8 | |
| Maximum | ND | ND | 45.6 | 5.6 | |
Values that do not have a common uppercase letter following them are significantly different (P < 0.05). ND, not determined.
Comparisons of mean percent prevalence or percentages of samples that were enumerable were made using a one-way ANOVA and Bonferroni's multiple-comparison posttest.
Comparisons of enumeration median values were made using the Kruskal-Wallis test for nonparametric data and Dunn's multiple-comparison posttest.
Enumeration values were determined in the winter and spring sampling seasons only.
Comparisons of percentages of samples that were enumerable were made using a two-tailed unpaired t test (t = 0.5948).
Comparisons of enumeration median values were made using a two-tailed Mann-Whitney U test.