A study has updated knowledge about the levels of Campylobacter and Salmonella on mutton.
The Food Standards Agency (FSA)-funded study looked at microbial contamination on sheep carcasses at abattoirs in England and Wales. This included culled ewes (sheep over twelve months) and lambs (sheep under twelve months). It was carried out in conjunction with studies funded by Defra and the PATH-SAFE research programme. The last survey of microorganisms on sheep carcasses in England and Wales took place in 2003.
Twelve of the 132 abattoirs in England and Wales took part, accounting for 28 percent of annual sheep abattoir production. The slaughterhouses ranged in turnover from 3,000 to 756,000 sheep killed annually.
A total of 1,282 carcass swabs were collected February 2023 to January 2024. All samples were tested for the isolation and quantification of Salmonella, 366 were tested for Campylobacter and 103 for Enterobacteriaceae; and E.coli.
E. coli and Enterobacteriaceae are commonly found in the intestines of most animals and are used in the food industry as indicators of hygiene.
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Salmonella was found in seven carcass swabs. Five isolates were of the sheep-adapted type with no confirmed association with human disease. The other two isolates were Salmonella Typhimurium, which causes human disease.
In Great Britain, 517 outbreak-associated cases of Salmonella were attributed to the consumption of lamb and beef products between 2015 and 2020, mainly due to Salmonella Typhimurium. Nearly 300 of these came from one outbreak.
Contamination with Campylobacter was found on 76 carcasses. The predominant species was Campylobacter jejuni.
The prevalence of E. coli at 88.4 percent and Enterobacteriaceae at 75 percent was as expected in freshly slaughtered meat, with 81.6 percent and 84.5 percent of these samples showing low levels of contamination, respectively.
There were no significant differences in infection rates between lambs and ewes.
Contamination on sheep carcasses was significantly lower than in cecal samples in the Defra study, suggesting that slaughter processes are effective in reducing contamination. Proper cooking and hygienic handling and preparation of mutton will further reduce microbiological contamination of the surface and minimize the risk to consumers.
However, the high numbers of Campylobacter and indicator organisms on some carcasses suggested that there was potential for improved slaughter practices.
The data generated can help inform industry and government decision-making, risk modeling and future microbiological risk assessments as part of trade negotiations.
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