In-vitro effect of nisin on Staphylococcus aureus pool isolates from Minas traditional cheeses from Campo das Vertentes-MG

Abstract

Minas traditional cheeses currently have a prominent role in the scientific depending on their social and economic importance to the country legally. Although the cheese can be marketed within the state, is notorious its presence outside of Minas Gerais. Because it is made with raw milk, the cheese has a risk for consumers to be potential carrier of pathogens such as Listeria, Salmonella and Staphylococcus aureus. The use of raw milk implies the need for studies to significantly decrease their contamination by S. aureus. Studies have shown that the addition of nisin to cheese manufacturing process can significantly reduce the contamination. The aim of this study was to evaluate the effect of Nisin on pool S. aureus isolates from traditional cheeses of Campo das Vertentes. Four levels (100, 200, 400 and 500 IU. mL^-1) of the commercial preparation Nisaplin ^® in autoclaved reconstituted skim milk at 10%. The analysis of S. aureus were made using 3M Petrifilm at zero; 3, 5, 8, 10, 12, 16, 24, 36, 48, 72, and 96 of incubation. There was no significant difference (p > 0.05) between control and doses of 200 IU mL^-1. However differences were observed between the other doses (p <0.05) in the two mentioned and also among themselves. The results of this study confirm those already made elsewhere showing that nisin can be effective in reducing counts of S. aureus in cheeses made with raw milk.