Biodiversity of Staphylococcus Species in Pecorino Siciliano Cheese

Some species of Staphylococcus found in dairy products can be important in the chesse ripening and particularly for the Protected Designation of Origin (PDO) cheeses. Bacteriological analysis was carried out and the bacteria were enumerated by surface plating on PCA and on Baird Parker. Fifty-four Gram-positive, catalase positive isolates from the core of Pecorino Siciliano cheese, a raw ewes's milk cheese, at different stages of ripening were identified phenotypically as members of the genus Staphylococcus. All the isolates were coagulase-negative, facultative anaerobes ans were, therefore, Staphylococcus species. No effort was made to identify them to species level. Pulsed Field Gel Electrophoresis (PFGE) analysis was used as a tool for examining overall genome similarity or divergence between isolates. Twenty-five different profiles were obtained with by PFGE, revealing the presence of a wide biodiversity among the strains. The results of the first study gave an overview of the population of staphylococci associated with Pecorino Siciliano cheese. Further studies will be required to study interaction among the predominant biotypes in relaton to the physicochemical properties of cheese, in order to protect the traditional raw milk cheeses.