Effects of nisin on Staphylococcus aureus count and physicochemical properties of Minas Frescal cheese

Abstract

The aim of this work was to evaluate the effects of nisin on in vitro and in situ Staphylococcus aureus counts. For in vitro experiment, milk was inoculated with 5.0 log cfu·mL(-1) of S. aureus and nisin was added at concentrations of 0, 100, 200, 400, and 500 IU mL(-1). The main effect of the bacteriocin was lag phase extension from 0h, for 0 and 100 IU·mL(-1) to 8h, when 200, 400, and 500 IU·mL(-1) of nisin were used; however, log phase was not affected. Microbial growth rate was found to be exponential and around 0.11 log cfu·mL(-1)·h(-1) for all treatments. For in situ experiments, 0, 400, and 500 IU·mL(-1) of nisin were directly added to pasteurized milk previously inoculated with 5.0 log cfu·g(-1) of S. aureus. Milk, curd, and whey were analyzed to S. aureus counts. Nisin at concentration of 500 IU·mL(-1) was able to reduce S. aureus count in curd and whey, demonstrating nisin partition between both phases. Throughout storage at 4°C, S. aureus count increased for all treatments, but the bacterial grew slower when nisin was added in both concentrations, maintaining S. aureus count about 1.5 log cycles lower than the control, despite abusive initial S. aureus count. Therefore, nisin seems to play an important role in reducing S. aureus initial count in cheese made with highly contaminated milk. Nisin showed potential to be used as an additional, important hurdle to improve Minas Frescal cheese safety, without replacing good manufacturing practices.

Natural Antimicrobial Edible Coatings for Microbial Safety and Food Quality Enhancement

“…Mitra and others () showed that the addition of nisin at a concentration of 1000 AU/mL to both skim milk and whole milk was effective in reducing the initial count of Pseudomonas fluorescens , Enterococcus italicus , Lactobacillus paracasei , Enterococcus mundtii , B. cereus , Enterococcus faecalis , Bacillus thuringiensis , and Acinetobacter spp, to an undetectable level during incubation at 8 °C for 8 to 20 h. In another study, a reduction of 1.2 and 2.0 log cycles in the S. aureus count has been noticed, respectively, after addition of nisin at 100 and 500 IU/mL to Minas traditional Serro cheese (Pinto and others ). Likewise, Felicio and others () reported the effectiveness of nisin in reducing the growth of S. aureus in Minas frescal cheese. Recently, de Oliveira and others () evaluated the antimicrobial potential of nisin against L. monocytogenes , B. cereus , Alicyclobacillus acidoterrestris , and S. aureus in mango, cashew, peach, and soursop juices.…”

Uso de nisina y quitosano para la inhibición de Staphylococcus aureus resistente a antibióticos y asociado a mastitis bovina

“…El efecto bactericida o bacteriostático de la nisina y el quitosano solos y en combinación, se determinó sobre dos bacterias multirresistentes seleccionadas. Lo anterior se realizó de acuerdo a Felicio et al (14) y Mirdamani et al (28) con algunas modificaciones. Tubos con caldo Mueller-Hinton conteniendo un inóculo de cada uno de los dos aislados de S. aureus ajustado a la turbidez del tubo 0.5 de la escala de McFarland, se mezclaron asépticamente con la CMI de la nisina, quitosano y del compósito nisina/quitosano.…”

“…El uso de péptidos antimicrobianos (PAMs) como la nisina y polisacáridos biodegradables como el quitosano, representan opciones atractivas (12,13) . La nisina es un péptido de 34 aminoácidos producido por Lactococcus lactis, el cual posee actividad antimicrobiana sobre un amplio rango de bacterias Gram positivas (12) , además de que es considerada como segura por la FAO (14) . Por su parte, el quitosano (poly β- [1][2][3][4]-Nacetyl-D-glucosamina) es un biopolímero lineal producido por la desacetilación química de la quitina, la cual se encuentra en el exoesqueleto de crustáceos e insectos.…”

Utilisation of water extract of green chilli pepper in the manufacture of low‐fat fresh cheese

“…The use of nisin has been suggested to prevent or suppress the growth of Staphylococcus aureus , prolong the shelf life and improve the safety of fresh cheese (Felicio et al . ). Dantas et al .…”

“…Fresh cheese can be made with goats' milk or a mixture of goats' and cows' milk to meet consumer demands (Sant'Ana et al 2013). The use of nisin has been suggested to prevent or suppress the growth of Staphylococcus aureus, prolong the shelf life and improve the safety of fresh cheese (Felicio et al 2015). Dantas et al(2016) manufactured probiotic fresh cheese using Lactobacillus casei Zhang as a functional dairy product that presents potential health benefits to provide a differentiated product to consumers.…”