Microbiological assessment at slaughter of chicken carcasses from commercial, backyard and semi-backyard production systems.

INTRODUCTION: Smaller scale, alternative, chicken production systems are gaining popularity globally. However, this brings public health and market confidence concerns, especially where there are no established standards of production. The aim of this study was to carry out a microbiological analysis of chicken carcasses from the commercial, backyard and semi-backyard production systems, slaughtered in the same slaughterhouse. METHODOLOGY: Samples of 102 chicken carcasses were taken in two steps of the slaughter (A: after bleeding; and B: after chiller tank) and were subjected to aerobic mesophilic, coliforms at 35 °C and coliforms at 45 °C counts, and Salmonella spp. detection. Salmonella spp. isolates were subjected to antimicrobial resistance analysis. RESULTS: At slaughter step A, carcasses from the backyard system had less contamination than carcasses from the commercial system, with a difference of 0.7 log10 CFU/mL. Salmonella was identified in carcasses of all production systems and in both slaughter steps. Nine chicken carcasses were positive for Salmonella and no significant difference was observed in the occurrence of Salmonella amongst the carcasses from different production systems. Two Salmonella isolates, that presented the highest resistance profiles (one isolate was resistant to eight and the other to six out of ten tested antibiotics), were identified on carcasses from the semi-backyard system. CONCLUSIONS: Carcasses from the backyard system had a lower microbial count at the initial step of the slaughter process than the commercial production system. In addition, greater resistance to antimicrobials was observed in Salmonella isolates from semi-backyard system.