Effect of Salt Ratios on Enterotoxin Production by Staphylococcus aureus in Fermented Sausage

This study was carried out to determine the effect of salt application at different rates (1, 1,5, 2, and 2,5%) on the ability of S. aureus to produce enterotoxin in fermented sausage, one of the most produced meat products in Turkey. Five different reference strains of S. aureus known to have the ability to produce A-, B-, C-, D-and E-type toxin were inoculated into the experimentally produced sausage dough at 106 cfu g-1. Chemical analysis of sausage samples were performed. The identification of S. aureus was confirmed by cultural and molecular methods. ELISA was used to determine the ability to produce enterotoxin, and classical PCR and multiplex PCR were used to detect enterotoxin genes. According to the analysis results, the moisture, aw and pH values of the sausage samples were 38,80-61,48%; 0,883-0,901; 5,41-6,33, respectively. In production groups, S. aureus count was detected between 4,59-6,52 log cfu g-1 on day 0; 6,41-8,92 log cfu g-1 on day 7; 7,23-8,91 log cfu g-1 on day 14 and 6,13-8,82 log cfu g-1 on day 21. It was determined that bacterial counts reached the highest levels on the 7th day (after fermentation) in all groups (p < 0,05). Despite the logarithmic increase observed in S. aureus numbers in sausage samples, no toxin production could be detected. This situation can be explained by the lack of enviromental conditions required for enterotoxin production, the presence of competitive microflora, the fact of although the strains are enterotoxigenic, there is no expression-dependent production in the food matrix, and the fermentation conditions in sausage do not provide the neccessary environment for enterotoxin production. As a result, the high bacterial counts detected in sausage samples pose a potential risk to public health. Although salt levels have a limited effect on enterotoxin production, other factors, especially the hurdle factors in sausage, help prevent enterotoxin production. This makes fermented sausage an important food in terms of food safety. In addition to ensuring adequate hygiene for traditional Turkish type fermented sausage production, attention should be paid to incorporating practices such as Hazard Analysis Critical Control Point (HACCP) and Good Manufacturing Practices (GMPs) at every stage of the production process, i.e. from farm to table.