EFFECT OF TYPE OF DEFEATHERING SYSTEM ON SALMONELLA CROSS-CONTAMINATION DURING COMMERCIAL PROCESSING

The cross-contamination effects of three commercial defeathering syste ms were compared using turkeys from a single Salmonella-positive flock (less than or equal to 15% cloacal-positive). Single or ''common'' fl ocks were used to control flock-to-flock variability. Thirty birds wer e mechanically defeathered in each system as the first flock of the da y and compared with 30 hand-defeathered (control) birds. Three trials, each using a different common flock, were completed. In Trial 1, the incidence of Salmonella-positive birds decreased following mechanical defeathering at all three processors. The incidence of Salmonella-posi tive carcasses in test flocks increased following steam-spray (similar to 100%) and kosher (similar to 50%) defeathering in Trials 2 and 3, whereas no increase in Salmonella-positive carcasses resulted from con ventional defeathering. The decrease in the number of Salmonella-posit ive birds as a result of defeathering observed in Trial 1, as compared to increases observed in Trials 2 and 3, may be related to the select ion of feather contaminated (Trial 1) vs intestinal-colonized (Trials 2 and 3) turkeys. Surface temperature of the carcasses and length of t ime required to defeather were monitored within each system. It is hyp othesized that the increases in the number of Salmonella-positive bird s following steam-spray and kosher defeathering in Trials 2 and 3 were a result of skin surface changes occurring during the defeathering pr ocess, which allowed increased adherence or entrapment of Salmonella s pp. on or within remaining skin layers.