Comparison of poultry exudate and carcass rinse sampling methods for the recovery of Campylobacter spp. subtypes demonstrates unique subtypes recovered from exudate

The carcass rinse procedure is a method commonly used for the detection of Campylobacter spp. on processed poultry products. Alternatively, carcass exudate (weep or drip), a viscous fluid comprised of blood and water that leaks into packaging, can also be sampled. It is unknown however if direct carcass rinse or exudate/weep can be utilized to preferentially recover different Campylobacter spp. subtypes. If there is a difference in subtypes recovered, the Campylobacter spp. subtypes from carcass rinse analysis may not be indicative of consumer exposure, as the exudate is the fluid to which consumers are potentially exposed to due to kitchen cross-contamination. Experiments were conducted to determine if there are differences in recovery of Campylobacter spp. subtypes between the two methodologies. The experiment was performed in triplicate using three flocks located on different farms. For each flock, 50 fecal samples were obtained on the farm, 25 carcass rinses during pre-chill processing, 25 carcass rinses during post-chill processing, and 50 samples from exudate from carcasses stored at 4 °C (25 after 2-day storage and 25 after 6-day storage). Each sample type was cultured for Campylobacter spp. Isolates recovered from positive samples were subtyped using flaA SVR (flagellin A-short variable region) DNA sequence typing and compared for relatedness. The data demonstrated that multiple subtypes of Campylobacter jejuni were present in a flock, and that subtypes present in a flock during production were also present on the final processed product. Subtypes recovered by the two recovery methodologies were similar based on flaA SVR classification. Combining the totals from all 3 flocks a total of 10 flaA SVR subtypes were recovered from post-chill carcass rinses and 9 subtypes recovered from 6-day exudate samples.