Assessing Campylobacter Colonization of Broiler Herds Ante Mortem and Monitoring Campylobacter Contamination Post Mortem by qPCR

Human campylobacteriosis is the most prevalent zoonosis, with chicken meat contributing substantially to the number of cases. Measures to avoid or at least reduce exposure by meat contaminated with Campylobacter (C.) spp. are needed. With regard to the process hygiene criterion introduced in 2018 for Campylobacter spp. on broiler carcasses, we evaluated the performance of a recently developed quantitative real-time PCR (qPCR) for C. jejuni/coli on random caecal samples and chicken meat. With the qPCR on pooled caecal samples not only C. jejuni/coli positive (69.6%) versus negative broiler herds (30.4%) were identified, but herds highly colonized with C. jejuni/coli (39.4%) could also be identified. From the chicken meat samples, 8.0% were positive for C. jejuni/coli by qPCR and 0.7% by enumeration (>10 cfu/g) compared to 58.3% using cultural enrichment. Given the higher sensitivity, the qPCR method could replace the currently used enumeration method to assess the process hygiene criterion for Campylobacter spp. on broiler carcasses. Moreover, with the qPCR, a reliable identification of C. jejuni/coli colonized incoming broiler herds a few days before slaughter is feasible, which provides important information to optimize slaughter processes. Finally, identifying and monitoring herds with high C. jejuni/coli colonization rates could help to individually improve biosecurity measures at farm level, eventually reducing the C. jejuni/coli load on chicken meat.