Evaluation of the correlation among the presence of enterotoxins encoding genes (SEA, SEB and SEC) of Staphylococcus aureus with microbial and chemical parameters in local cheese

Local dairy products are one of the most important sources of growth and production of enterotoxin by species of Staphylococcus bacteria. Hence¡ the aim of this study was to isolate Staphylococcus bacteria and identify Staphylococcus aureus enterotoxins encoding genes by molecular methods (SEA¡ SEB and SEC) as well as determining any probable correlation among the presence of the enterotoxin encoding genes with microbial and chemical parameters in Kalat city local cheese. For this purpose¡ 30 samples of local cheese were collected and transferred from Kalat city to the laboratory under sterile conditions. Samples were then cultured on Bread Parker Agar Medium and serological identification was done using coagulase method. PCR was performed according to16SrRNA gene in order to identify the species of isolated bacteria. Also¡ the SE serotype enterotoxin genes in each bacterium were examined. Results showed that 100% of samples are contaminated with Staphylococcus aureus. Also¡ PCR results showed that 70% of the isolated Staphylococcus aureus produce one of the enterotoxins. The frequency of SEA¡ SEB and SEC genes in the isolated Staphylococcus aureus¡ were respectively 36.6%¡ 36.6% and 0%. Also¡ only 3% of Staphylococcus aureus were containing both SEA and SEB genes. The correlation coefficients of the presence of genes SEA and SEB with a range of pH¡ salt¡ acidity¡ moisture%¡ mesophilic bacteria total count and enumeration of Staphylococcus aureus were0.733-0.505¡ 0.5360.690¡ 0.797-0.924¡ 0.632-0.788¡ 0932-0935 and 0.427-0.629¡ respectively.