Resumen

CASTRO, Gustavo et al. Comparation of Nisin and Lactococcus lactis subsp. lactis Cultures for Biopreservation of White Cheese.. Rev. Cient. (Maracaibo) [online]. 2009, vol.19, n.2, pp.201-123. ISSN 0798-2259.

The main disease transmitted by foods in Venezuela is the staphylococci poisoning, and it is white cheeses the most involved food. The nisin is a bacteriocin able to inhibit the growth of Gram positive microorganisms; among them, Staphylococcus aureus. One of the limitations of its use is its high cost. The use of bacteriocin producing starter cultures represents an alternative for milk industry. The objective of the present study was to evaluate the biopreservating effect of the Lactococcus lactis subsp. lactis (ATCC 11454) and to compare it with the addition of nisin to milk. Five types of cheese from pasteurized milk were elaborated: control; addition of L. lactis; addition of L. lactis and S. aureus; addition of S. aureus; addition of nisina and S. aureus. Both, microbiological and physical-chemical determinations were made according to COVENIN. The nisin concentration was measured using the agar diffusion technique. The data was analyzed with an analysis of variance and testing the means by the method of least squares means. The starter cultures produced nisin, but in low amounts. In cheeses elaborated with milk inoculated whit S. aureus (10³ ufc/mL), no inhibiting effect of the culture on this pathogenic microorganism was observed. Nevertheless, cheeses elaborated with both, Lactococcus without inoculation of Staphylococcus and with nisin, presented little growth of Staphylococcus and coliforms. Nisin was more efficient to obtain biopreservation of white cheeses, although the use of producing bacteriocin starter culture, allowed to obtain cheeses with low counts of pathogens, if the initial contamination of the milk was low.

Palabras clave : Nisin; Lactococcus lactis; white cheese; biopreservation.