Risk factors for the contamination of broilers with Campylobacter and Salmonella at slaughterhouses

Alemán. In 2008 a European wide survey (2007/516/EC), was conducted to estimate the prevalence of Campylobacter spp. and Salmonella spp. in broiler flocks and carcasses. We analysed the German data with the aim of investigating factors related to the bird, farm and the slaughter house as potential risk factors for a detection of these agents in the samples.Methods: The sampling frame was proportional to the slaughterhouse capacity in Germany. A sample consisted of 10 caeca of birds from one flock analysed for Campylobacter and one carcass of the same flock analysed for Salmonella and Campylobacter .Results: In the survey 432 samples were investigated. In the multivariate model the contamination of the caecum with Campylobacter as a function of age over 36 days, number of birds in the flock, thinning, having received antimicrobials and seasonal effects was investigated. Remaining factors in the model were age over 36 days at slaughter OR 2.1(95%CI1.4-3.1) in comparison to below 36 days and month with over 10°C OR 3.0(95%CI1.9-4.5) in comparison to colder months. The contamination of the carcass with Campylobacter was investigated with the model of the caecum and the additional factors cooling technology and test result of the caeca from the batch. Batch positive in the caeca was the remaining explanatory variable for a contamination of the carcass OR 13.4 (95%CI 8.2-21.9). The contamination of the carcass with Salmonella was investigated with the same variables as in the caeca model. One additional term was prevalence of over 60% Campylobacter in the slaughterhouse. The type of chilling OR 1.8 (95%CI 1.1-3.2), (immersion and spray versus air cooling) and a prevalence of Campylobacter more than 60% in the slaughterhouse OR 2.1 (95%CI 1.2-3.6) were significant risk factors for the detection of Salmonella on the carcasses.Conclusion: Campylobacter positive broiler flocks increased the odds of positive carcasses. Older birds were more likely to carry Campylobacter in the caecum. Cooling technology and overall hygiene have a significant impact on the Salmonella load on chicken carcasses