Presencia de Staphylococcus aureus en quesos comercializados en la ciudad de Milagro, octubre – noviembre 2013

Staphylococcus aureus is gram-positive cocci present in the environment, water, air, and food. They are often present in dairy products and food with high salt content such as sausages. The objective of this study was to determine the presence of Staphylococcus aureus in cheese marketed in Milagro city, by conducting a descriptive, prospective, and transversal study. The study was conducted from October to November 2013. A total of 54 cheese samples coming from three types of processing variations (fresh, pasteurized and mozzarella) were analyzed by isolation in selective growth medium (Baird-Parker agar), gram staining, and bacteriological diagnostic methods: catalase, coagulase, and saline mannitol. The samples were collected from 3 markets in Milagro, resulting in an incidence of S. aureus in 30 out of the 54 cheese samples studied (55%). Also, the presence of the bacteria in the different cheese variations was as follows: in 18 handmade (fresh) cheese pieces (100%); in 11 pasteurized cheese pieces (61%); and, in 1 mozzarella cheese (5%). These results reveal an imminent risk for consumers because they have whole toxins that can lead to death from poisoning. This research complied with the NTE INEN 1529-2, NTE INEN 1529-14: 98, NTE INEN 2584: 2013 standards and CLSI (Institute of Laboratory Standardization).