engleski

Identification of enterotoxin genes in coagulase-positive staphylococci isolated from retail foods

Staphylococci are ubiquitous bacteria that can be found in warm blooded animals, humans, enviroment, food processing plants, foods etc. Their presence in food and connection with food borne disease outbrakes (FBDOs), is likely to be conected with human as a contamination source. The food borne disease occurs from the ingestion of staphylococcal enterotoxins (SEs) preformed in food by enterotoxigenic strains of coagulase-positive staphylococci (CPS), mainly Staphylococcus aureus. SEs are heat stable and can be present in food when staphylococci can not be detected. To date, 21 different SE serotypes (SEA to SEE, SEG to SEV) have been described, and six of them have been prooved to be involved in FBDO: SEA (the most commonly detected) to SEE, SEH. In this study we examined the presence of CPS in different retail food types: chicken meat, pork meat, mechanically deboned pork meat. cheese (soft, semi-hard and hard), sour cream, sausage (semi-dry fermented and fermented). A total of fifty-five retail food samples were examined according to HRN EN ISO 6888-1:2004 standard method and eighteen (32.7%) were found to be positive on CPS. These positive strains of CPS were then analyzed by PCR for the presence of SE genes (SEA, SEB, SEC, SED, SEE). In four strains (22.2% of CPS) SE genes were detected: SEB (soft cheese made from unpasterized milk), SEA and SED (two strains isolated from chicken meat, one sample positive for both genes) and SEC (semi-hard cheese sample). SEE was not found in any of coagulase positive strains. The presence of CPS and confirmation of SE genes in analyzed food types represents a potential health risk for consumers. It is therefore important to follow all hygienic and sanitiary measures to prevent and limit contamination of food and possible food borne disease outbrakes.

coagualse-positive staphylococci; enterotoxins

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