Evaluation of staphylococcal food contamination in four different culture media

The efficiency of Baird-Parker agar, mannitol-salt agar, Vogel-Johnson agar and Giolitti-Cantoni broth for the detection of Staphylococcus aureus from food samples, was studied by comparing the numbers of Staphylococcus recovered from the samples, the degree of selectivity reached and the recovery of coagulase and thermonuclease positive staphylococci. Lowest counts of Staphylococcus were obtained with Giolitti-Cantoni broth. The mannitol-salt agar proved to be the most efficient media system with respect to the number of staphylococci recovered and the degree of selectivity reached. None of these media was highly selective for the isolation and detection of S. aureus; therefore, it is necessary to identify the isolated colonies in all cited media, in order to use rightly the current guidelines for microbiological quality of foods.