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Isolation of a bacteriocin‐producing Lactococcus lactis subsp. lactis and application to control Listeria monocytogenes in Moroccan jben
Author(s) -
Benkerroum N.,
Oubel H.,
Zahar M.,
Dlia S.,
FilaliMaltouf A.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.01199.x
Subject(s) - bacteriocin , lactococcus lactis , listeria monocytogenes , nisin , listeria , microbiology and biotechnology , food science , bacteria , biology , lactococcus , strain (injury) , fermentation , isolation (microbiology) , lactic acid , antimicrobial , genetics , anatomy
Aim: Use of a bacteriocin‐producing lactococcal strain to control Listeria monocytogenes in jben. Methods and Results: A Lactococcus lactis strain isolated from lben was shown, by the spot technique, to produce a bacteriocin different from nisin. Inhibitory activity of the bacteriocin‐producing strain against Listeria monocytogenes was investigated in jben, made from cow's milk fermented with the producer organism and contaminated with 10 4 or 10 7 cfu ml −1 . Listeria counts were monitored during manufacture, and during conservation at room and at refrigeration temperatures. Results showed that the pathogen was reduced by 2·7 logarithmic units after 30 h of jben processing when the initial inoculum of 10 7 cfu ml −1 was used. For the initial inoculum of 10 4 cfu ml −1 , the bacterium was completely eliminated at 24 h. Furthermore, the use of the bacteriocin‐producing starter culture extended the shelf‐life of jben by 5 days. Conclusions: In situ production of the lactococcal bacteriocin is an efficient biological means of controlling L. monocytogenes in jben and of allowing shelf‐life extension. Significance and Impact of the Study: The proposed technology will essentially benefit minimally processed dairy products and those made with raw milk.