Abstract

ALVAREZ BADEL, Beatriz et al. Effect of nisin on the inhibition of the growth of Staphylococcus areus and on the sensory properties of coastal cheese. Rev. mex. de cienc. pecuarias [online]. 2022, vol.13, n.1, pp.272-286.  Epub June 06, 2022. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v13i1.5741.

Staphylococcus aureus is a common cause of food poisoning in humans. It is very common in dairy products made with raw milk, such as costeño cheese, an artisanal cheese common on Colombia’s Caribbean coast. Costeño cheeses from Montería, Colombia, were analyzed to quantify their S. aureus load, the effect of added nisin in inhibiting S. aureus growth in this matrix and on product sensory characteristics. Staphylococcus aureus was isolated from commercial costeña cheeses and the minimum inhibitory concentration (MIC) of nisin versus this microbe quantified. Costeña cheese was made containing 0, 500 and 625 IU/kg added nisin, S. aureus counts done at 0 and 24 h storage, and the results analyzed using a random design with 57 experimental units. Sensory evaluation was done with a triangular test involving a panel of 40 tasters to identify any differences in the sensory characteristics of costeño cheese with and without 500 IU/kg added nisin. All the commercial costeño cheeses were contaminated with S. aureus, but all identified strains were inhibited by 500 IU/ml nisin (MIC). Addition of nisin during cheese production reduced (P≤0.05) S. aureus counts compared to a nisin-free control; at 24 h, nisin lowered S. aureus counts 2.3 log cycles in the 500 IU/kg nisin treatment and 1.9 log cycles in the 625 IU/kg treatment. Sensory characteristics did not differ (P≥0.05) between costeño cheese containing 500 IU nisin/kg and a nisin-free control. Addition of 500 IU/ml nisin to costeño cheese can inhibit S. aureus growth without affecting sensory characteristics.

Keywords : Bactericides; Minimum inhibitory concentration; S. aureus.

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