Analyzing slaughter modalities and environmental factors to improve prediction of Campylobacter concentration in broiler carcasses

Campylobacter, the most prevalent European bacterial foodborne pathogen, linked to poultry, poses challenges for French food manufacturers in meeting European regulatory hygiene limits for Campylobacter on broiler carcasses, highlighting the need to identify contamination sources to implement corrective measures. This study aimed to identify the factors influencing Campylobacter contamination on broiler neck skin after chilling, by comparing two automated slaughterhouses with different contamination levels. Several statistical regression approaches were applied to data collected in both slaughterhouses, i.e. Campylobacter contamination in the air at different locations of the slaughterhouses and in the scalding bath, as well as on broiler cecal contents and neck skin, and recorded variables associated with operational slaughter settings. Several key contributors were identified, in order of importance: slaughter line speed, chilling efficiency, air contamination in the evisceration room, cecal contamination and air contamination at the hanging and plucking steps. Among these, cecal contamination and slaughter line speed were strong predictors of neck skin contamination after chilling. This study highlighted the importance of both environmental factors and slaughter process in determining Campylobacter levels on broiler neck skin after chilling. A better understanding of these influences can support improved control strategies such as adjusting line speed and optimizing chilling, to reduce contamination and comply with regulatory limits.