TABLE 5.
Mean percent prevalence and load of E. coli O157:H7 on cull cattle hides and carcasses analyzed by plant
| E. coli O157:H7 parameter | Value for planta:
|
P value | |||
|---|---|---|---|---|---|
| A | B | C | D | ||
| Hide | |||||
| Prevalence (%) (±SD) | 29.9 ± 20.2A | 28.0 ± 15.9A | 64.0 ± 23.8B | 65.9 ± 21.6B | 0.0005b |
| Load (CFU/100 cm2) | |||||
| Enumeration positive (%) (±SD) | 0.9 ± 1.4A | 0.3 ± 0.5A | 1.6 ± 1.6A | 8.6 ± 8.0B | 0.0013b |
| n | 7 | 2 | 12 | 65 | |
| Median | 120 | 80 | 60 | 80 | 0.7125c |
| Minimum | 40 | 80 | 40 | 40 | |
| Maximum | 4.0 × 102 | 80 | 6.0 × 102 | 9.8 × 103 | |
| Preevisceration carcass | |||||
| Prevalence (%) (±SD) | 11.5 ± 12.8A | 6.9 ± 4.6A | 6.9 ± 5.8A | 41.5 ± 21.6B | <0.0001b |
| Load (CFU/100 cm2)d | |||||
| Enumeration positive (%) (±SD) | 0.8 ± 1.0 | 8.7 ± 7.8 | 0.0927e | ||
| n | 0 | 0 | 3 | 33 | |
| Median | 0.8 | 1.6 | 0.5281f | ||
| Minimum | 0.8 | 0.8 | |||
| Maximum | 5.6 | 45.6 | |||
Values that do not have a common uppercase letter following them are significantly different (P < 0.05).
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 = 1.998).
Comparisons of enumeration median values were made using a two-tailed Mann-Whitney U test.