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Potential application of the nisin Z preparation of Lactococcus lactis W8 in preservation of milk
Author(s) -
Mitra S.,
Mukhopadhyay B.C.,
Biswas S.R.
Publication year - 2011
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2011.03075.x
Subject(s) - nisin , food spoilage , food science , lactococcus lactis , pasteurization , enterococcus faecalis , skimmed milk , enterobacter aerogenes , microbiology and biotechnology , enterococcus faecium , preservative , enterococcus , bacteria , biology , lactic acid , staphylococcus aureus , antimicrobial , genetics , biochemistry , escherichia coli , gene , antibiotics
Aims: The aim of the study is to evaluate the effectiveness of the preparation of nisin Z from Lactococcus lactis W8‐fermented milk in controlling the growth of spoilage bacteria in pasteurized milk. Methods and Results: Spoilage bacteria isolated from pasteurized milk at 8 and 15°C were identified as Enterococcus italicus , Enterococcus mundtii , Enterococcus faecalis , Bacillus thuringiensis , Bacillus cereus , Lactobacillus paracasei , Acinetobacter sp., Pseudomonas fluorescens and Enterobacter aerogenes. These bacteria were found to have the ability to survive pasteurization temperature. Except Enterobacter aerogenes , the spoilage bacteria were sensitive to the nisin Z preparation of the L. lactis W8. Addition of the nisin Z preparation to either the skim milk or fat milk inoculated with each of the spoilage bacteria reduced the initial counts (about 5 log CFU ml −1 ) to an undetectable level within 8–20 h. The nisin Z preparation extended the shelf life of milk to 2 months under refrigeration. Conclusions: The nisin Z preparation from L. lactis W8‐fermented milk was found to be effective as a backup preservative to counteract postpasteurization contamination in milk. Significance and Impact of the Study: A rapid inhibition of spoilage bacteria in pasteurized skim and fat milk with the nisin Z preparation of L. lactis W8 is more significant in comparison with the commercially available nisin (nisin A). The nisin Z preparation can be used instead of commercial nisin, which is not effective in fat milk.