Staphylococcal food poisoning from sheep milk cheese

Abstract

SUMMARYCheese made from sheep milk was implicated in food-poisoning incidents in December 1984 and January 1985. Bacteriological examination of batches of cheese failed to reveal a viable pathogen but enterotoxin A produced byStaphylococcus aureuswas present. This was the first time that enterotoxin was detected in a food produced in the UK which was associated with poisoning and from which viableStaph. aureuscould not be isolated. Subsequent detailed examination of milk, yoghurt and cheese from the same producer revealed that contamination withStaph. aureuswas associated with post-infection carriage as well as clinical illness in ewes on the farm. Strains producing enterotoxin A were still intermittently present in the bulk milk used for cheese production nearly 2 years afterwards, apparently in the absence of clinical illness in the sheep. The possible effects of heat treatment are discussed. Any changes in legislation should cover all non-human mammalian milk used for human consumption.