부산대학교 도서관

Background: Staphylococcal food poisoning (SFP) is an intoxication caused by the ingestion, with food, of emetic staphylococcal enterotoxins (SEs) produced by enterotoxigenic strains of coagulase positive staphylococci (CPS): especially Staphylococcus aureus. Staphylococci are commonly found in humans and in a wide variety of animals. The contamination of food with CPS is commonly caused by inadequate food processing methods or the use of mastitic milk. In case of staphylococcal mastitis of ruminants, S.aureus can be carried over from the udder into milk. Thus unpasteurized milk cheeses, contaminated by enterotoxigenic strains of staphylococci, may be involved in SPF outbreaks. Methods & Materials: During August 2015 symptoms referable to SFP were described in a group of excursionists after eating raw milk cheese produced in a south tyrolean malga (shepherd hut). As consumption of cheese has been supposed to be a common risk factor, the case has been reported to the Local Veterinary Service that tried to rule out the source of the outbreak in cooperation with IZSVe-laboratory. Cheese sample, bulk tank milk and individual milk samples from the 41 dairy cows, rared at the malga, were collected. Food sample were analyzed for SEs type A, B, C, D performed according to the EU-RL screening method for CPS v5 (extraction followed by dialysis concentration and immuno-enzymatic detection). CPS were counted in cheese according to ISO 6888-2:1999. CPS were tested for SEs genes by PCR and biotyped for addressing host specificity by Italian National Reference for CPS. Results: Mean value of CPS in cheese was 2600 cfu/g and presence of SEs was confirmed (test value > 2,20). S.aureus have been isolated from bulk tank milk and from 23,8% of individual milk samples. Just one of the 41 cows was reported with clinical mastitis. CPS were submitted to antibiogram without encountering any detectable resistance. S.aureus strains have been submitted to PCR test for genes encoding SEs. Conclusion: Bacterial contamination of raw milk can occur even under optimal hygiene conditions, and the discrimination of the toxigenic nature of the strains can facilitate the management of potentially risky situations. Importance of SFP for public health justifies further investigation. [ABSTRACT FROM AUTHOR]