Microbiological contamination of sheep carcases in Finland by excision and swabbing sampling

The aims of this study were to provide data on the microbiological contamination of sheep carcases slaughtered in Finland, and to compare excision and swabbing methods for microbiological sampling of sheep carcases. The results were also compared to the requirements laid down in Regulation (EC) No 2073/2005. A number of 50 sheep carcases were sampled both by excision and by swabbing with gauze at four slaughterhouses. The samples were analysed for total viable counts (TVCʹs), Enterobacteriaceae, and Escherichia coli. The same carcases were also sampled for Salmonella spp. by swabbing. The mean levels of TVCʹs and Enterobacteriaceae, and the results for Salmonella spp. were in line with the requirements laid down in Regulation (EC) No 2073/2005. The mean levels of TVCʹs for samples by excision and by swabbing were 3.77 log CFU/cm2 and 3.16 log CFU/cm2, respectively. Enterobacteriaceae were recovered from 72% and 76% of the carcases, and E. coli from 48% and 61% by excision and swabbing, respectively. No carcases were found positive for Salmonella spp. The mean levels of TVCʹs, Enterobacteriaceae and E. coli were significantly higher for the samples by excision than for the samples by swabbing. When the relationship between the sampling methods were analysed, the results for excision samples and swabbing samples were related for the TVCʹs, and there was a significant correlation between the sampling methods for Enterobacteriaceae. The results suggest that swabbing by gauze can be used as an alternative sampling method to excision. In addition, a significant correlation was seen between the results for Enterobacteriaceae and E. coli for the samples collected by swabbing, suggesting that E. coli can be used as an indicator bacterium instead for Enterobaceteriaceae for sampling of sheep carcases by swabbing.