Summary:
Frequency and numbers of Campylobacter spp. were assessed per freshly processed, contaminated broiler carcass. Campylobacter-positive flocks were identified by cecal sample analysis at slaughter. These flocks had been tested as Campylobacter negative at 4.1 ± 0.9 d prior to slaughter. Levels of contamination were estimated using 2 sampling approaches per carcass: (1) free weep fluids and (2) whole-carcass, 100 mL of distilled water rinses. Estimations of counts were determined by directly plating dilutions of weeps and rinses onto Campy-Cefex agar and incubating the plates at 41.5 ° C under microaerobic atmosphere. Confirmation was provided by latex agglutination to quantify levels per milliliter of weep and per 100 mL of rinse. Thirty-two slaughter groups (∼20 carcasses per group) were compared from 2003 to 2004. The Campylobacter-positive weep frequency was 84.8%, whereas the frequency for rinse samples was 74.4% (P <0.001). Enumeration of Campylobacter spp. on positive samples ranged from 0.70 to 6.13 log10 cfu / mL of weep (geometric mean of 2.84) and from 2.30 to 7.72 log10 cfu / 100 mL of rinse (geometric mean of 4.38). The correlations between weep and rinse were 0.814 with 0.5 mL of rinse and 0.6294 when applying 0.1 mL of rinse The quantitative regression analyzes for these 2 corresponding tests were log10 rinse (for 0.5 mL of inoculum) = 1.1965 log10 weep + 0.4979, and log10 rinse (for 0.1 mL of inoculum) = 1,322 log10 weep - 0.1521. FlaA SVR sequencing of isolates indicated that the same genotypes were found in weep and rinse samples. Weep and rinse sampling led to different proportions of Campylobacter-positive carcasses detection, but we demonstrated that this difference was reduced by increasing the amount of rinse fluid used for plating.