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Despite extensive Salmonella controls used at processing, 5.5% of salmonellosis cases are linked to turkey. This study had two objectives: i) to summarize USDA-FSIS turkey Salmonella verification program data and ii) to evaluate Salmonella through turkey production and processing of 22 flocks. In objective 1, USDA-FSIS data shows the average Salmonella prevalence in ground turkey from 2016-2022 was 15.9%, and that the leading serovar changes frequently. For objective 2, bootsocks (n=22) were collected on-farm right after load-out. At processing, pre-scald wingtips (n=6 composites of 10/flock), pre-chill wingtips (n=6 composites of 10/flock), mechanically separated turkey (MST; n=6 bins/flock) and ground turkey (n=6 bins/flock) were collected. Salmonella prevalence was determined by a commercial qPCR and culture confirmed. In 33.2% of PCR-positive samples, Salmonella was not confirmed by culture, highlighting a discrepancy between molecular and culture detection. On-farm, 8/22 flocks were Salmonella positive, compared to 21 flocks that were positive at one or more processing locations, including 18 flocks that were positive in at least one final product sample. A logistic regression showed higher Salmonella prevalence in pre-scald (53.8%) than in pre-chill (18.2%), MST (27.3%) or ground turkey (26.5%). CRISPR-SeroSeq analysis of 148 culture positive samples detected 18 Salmonella serovars and showed 35.1% of samples contained multiple serovars. In 16 flocks, one or more serovars detected in final products were absent from any upstream samples. Two thirds of final product samples containing serovar Typhimurium typed as a live-attenuated Typhimurium vaccine strain. Salmonella on-farm and at pre-scald did not reflect Salmonella observed in final product. This data underscores the complexity of serovar tracking in turkey production and highlights challenges to identify surveillance samples that accurately represent Salmonella in turkey products.
Cason et al. (Thu,) studied this question.