Significance of coagulase-positive staphylococci for microbiological food safety

Abstract

Staphylococcal foodborne intoxication, in which major symptoms are vomiting and diarrhoea, occurs after ingestion of thermostable staphylococcal enterotoxins produced in food by enterotoxigenic strains of coagulase-positive staphylococci. Staphylococcal enterotoxins are normally not or only slightly inactivated during food processing, storage, distribution or during the preparation of the food in the kitchen. Therefore, if enterotoxigenic staphylococci are able to grow in food to more then 105 - 106 cfu/g/ml before they are killed there is still a risk of intoxication with consumption. The legislation of the Republic of Serbia lays down criteria for coagulase- positive staphylococci in food. However, the number of coagulase-positive staphylococci may not always be a good indicator of the presence of staphylococal enterotoxins, and the number of cells may have already decreased although the product still contains enterotoxins. The microbiological criteria for coagulase-positive staphylococci and/or staphylococcal enterotoxins in food are essential and useful to protect public health.

Alimentarne intoksikacije hranom, kod kojih je glavni simptom povraćanje i dijareja, nastaju posle unosa enterotoksina koje su u hrani stvorili enterotoksogeni sojevi koagulaza pozitivnih stafilokoka. Enterotoksini stafilokoka se normalno ili veoma malo inaktivišu za vreme procesa proizvodnje, skladištenja, distribucije ili za vreme kulinarske pripreme hrane. Stoga, ukoliko koagulaza pozitivne stafilokoke mogu da se razmnožavaju u hrani do broja većeg od 105 – 106 cfu/g/ml pre nego što budu uništene, konzumiranje takve hrane predstavlja rizik od intoksikacije. U "Pravilniku o mikrobiološkoj ispravnosti namirnica u prometu" (Sl. list SRJ 26/93) propisani su kriterijumi za koagulaza pozitivne stafilokoke u hrani. Međutim, broj koagulaza pozitivnih stafilokoka nije uvek dobar indikator za prisustvo enterotoksina stafilokoka, budući da broj ćelija može da se smanji, a da enterotoksin bude prisutan u hrani. Mikrobiološki kriterijum za koagulaza pozitivne stafilokoke i/ili enterotoksine stafilokoka u hrani su neophodni i korisni za zaštitu zdravlja ljudi.