Detection of chicken carcasses contaminated with Salmonella enterica serovar in the abattoir environment of Taiwan

Although a nation-wide microbiological screening program of chicken carcasses after chilling in Taiwanese chicken abattoirs has been undertaken since 2006, little is known regarding the potential sources of the Salmonella during the slaughter process. The present study provides data on the detection and serotypes of Salmonella isolated from broilers during processing and from the environment in six abattoirs in Taiwan. Overall, Salmonella were detected in 156 of 622 samples (25.1%; 95% CI: 21.7-28.7) collected. The prevalence of Salmonella varied between sampling sites with 5.8, 17.6, 31.3 and 35.5% of cloacal swabs, environmental samples prior to processing, environmental samples during processing and carcass rinse fluid, respectively, being positive (χ^{2} = 51.3, p < 0.0001). A total of 15 serotypes were identified from the 156 Salmonella isolates with S. Albany (41.7%) S. Schwarzengrund (20.5%), S. Kentucky (12.8%) and S. Tennessee (5.1%) being the most commonly isolated serotypes. Characterization of 156 isolates by Pulse Field Gel Electrophoresis (PFGE) identified 50 PFGE types. Typing confirmed the presence of the same PFGE type at multiple stages during processing including plucking, evisceration, chilling and post-chilling. The abattoir environment and intestinal contents of chickens are important sources of Salmonella in broiler chicken abattoirs, with the same PFGE types detected at different stages of processing both before and during slaughtering. It is concluded that Salmonella isolates present in the environment and intestinal contents of processed birds survived in the abattoir environment resulting in subsequent carcass contamination along the processing chain including plucking, evisceration, chilling and post-chilling.