Purpose: The aim of this study was to investigate the effects of selected slaughter process stages on the microbiological contamination of broiler carcasses in three large-scale Swiss abattoirs.
Methods: Broiler carcasses from three abattoirs were examined at five process stages (scalding, plucking, evisceration, washing, chilling) for total viable counts (TVC), Enterobacteriaceae, Escherichia coli and Campylobacter. At each stage and abattoir, 90 carcasses (pooled neck and breast skin) from 30 flocks were sampled. In addition, 48 carcasses sampled before scalding and 156 scalding water samples were examined for TVC and Campylobacter.
Results: With regard to TVC, Enterobacteriaceae and E. coli, distinct reductions were evident from delivered broilers to chilled carcasses and trends of respective results were comparable in the abattoirs (mean TVC at abattoirs: 7.6 – 7.8 log CFU/g before scalding, 6.0 – 6.5 log CFU/g after scalding, 4.6 – 4.9 log CFU/g after plucking, 4.2 – 4.4 log CFU/g in the chiller). With regard to Campylobacter counts on broiler carcasses, abattoir-specific differences after scalding were striking (probably associated with varying temperature/time expositions), plucking slightly increased the counts, whereas results remained mainly constant at the following stages (mean Campylobacter counts at abattoirs: 2.3 – 3.3 log CFU/g after scalding, 2.7 – 3.6 log CFU/g after plucking, 2.5 – 3.4 log CFU/g in the chiller).
Significance: Such abattoir-specific data form the basis for implementing targeted and sustainable measures at selected slaughter process stages (cost-benefit analysis) in order to reduce carcass contaminations and the introduction of pathogenic bacteria into the food chain.