Abstract

CAVA, Rita; SANGRONIS, Elba; LUCCI, Elisabetta  and  WOYZECHOWSKY, Lidia. Effect of the addition of nisin to fresh "telita" cheese on the survival of Staphylococcus aureus. An Venez Nutr [online]. 2006, vol.19, n.2, pp.69-73. ISSN 0798-0752.

In this study, the inhibiting effect of two concentrations (16.7 and 10.0 mg/kg) of nisin on the population of Staphylococcus aureus present on fresh "telita" cheese stored at 8 ± 2 ^oC for one month was determined. "Telita" cheese without nisin was used as control. Using the official methodology, the population of S. aureus, the water activity, and the pH were determined to the samples taken at weeks 0, 1, 2, 3 and 4 of storage. Nisin significantly decreased (p<0.05) the number of viables cel at 2 weeks storage time, the decrease was 0.77; 0.56; 0.82 y 0.59 log units in AIII, BI, BII y BIII, respectively. An increase in the population of the microorganism with storage time was observed in the control samples. The inhibiting effect of nisin on S. aureus depended on the amount of nisin added to the product and of the initial microbial load of the microorganism originally present in the cheese. It is concluded that the addition of nisin to the "telita" cheese decreases the survival of S. aureus, and therefore it could be used as an antimicrobial agent of natural origin that would improve the microbiological quality of fresh cheese made following good manufacturing practices (GMP).

Keywords : "Telita" cheese; Staphylococcus aureus; nisin; bacteriocins; fresh cheese.