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Lyophilized preparations of bacteriocinogenic Lactobacillus curvatus and Lactococcus lactis subsp. lactis as potential protective adjuncts to control Listeria monocytogenes in dry‐fermented sausages
Author(s) -
Benkerroum N.,
Daoudi A.,
Hamraoui T.,
Ghalfi H.,
Thiry C.,
Duroy M.,
Evrart P.,
Roblain D.,
Thonart P.
Publication year - 2005
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 - 10.1111/j.1365-2672.2004.02419.x
Subject(s) - listeria monocytogenes , starter , lactococcus lactis , bacteriocin , fermentation , food science , microbiology and biotechnology , fermentation starter , biology , lactic acid , listeria , bacteria , nisin , lactobacillus , lactobacillus sakei , chemistry , antimicrobial , genetics
Aim: Study of the effectiveness of in situ bacteriocin production by lactic acid bacteria (LAB) to control Listeria monocytogenes in dry‐fermented sausages. Methods and Results: Two bacteriocin‐producing strains: Lactococcus lactis subsp. lactis LMG21206 and Lactobacillus curvatus LBPE were grown in a pilot scale fermentor and lyophilized to be directly used in dry sausage fermentation. A commercial starter culture (Bel'meat TM SL‐25) not inhibitory to L. monocytogenes (Bac − starter) was mixed (1 : 1) with each of the two lyophilized bacteriocin‐producing strains to obtain starters active against the pathogen (Bac + starter). Anti‐ Listeria effectiveness of the Bac + starters was studied in dry‐fermented sausages. The meat batter was experimentally contaminated with a mixture of four different strains of L. monocytogenes (10 2 –10 3 CFU g −1 ). The results showed that L. monocytogenes did not grow in any of the contaminated batches, but no significant decrease ( P > 0·05) was observed either in the positive control (no added starter culture) or in samples fermented with the Bac − starter culture during the fermentation period and up to 15 days of drying. When the Bac + starter contained Lb. curvatus LBPE, cell counts of L. monocytogenes decreased to below the detectable limit (<10 CFU g −1 ) after 4 h of fermentation and no survivors could be recovered by enrichment beyond day 8 of drying. When the Bac + starter culture containing Lc. lactis LMG21206 was used, a decrease in Listeria counts to below the detectable limit was achieved after 15 days of drying. Conclusions: The bacteriocin‐producing strains studied may be used as adjunct cultures for sausage fermentations to control the occurrence and survival of L. monocytogenes . Significance and Impact of the Study: Addition of the Bac + strains, especially the Lb. curvatus strain would provide an additional hurdle to enhance the control of L. monocytogenes in fermented meat products.