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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 376428, 8 pages
http://dx.doi.org/10.1155/2012/376428
Research Article

Antilisterial Activity of Nisin-Like Bacteriocin-Producing Lactococcus lactis subsp. lactis Isolated from Traditional Sardinian Dairy Products

Department of Experimental Biology, Section of Hygiene, University of Cagliari, Cittadella Universitaria, S.S. 554, Km. 4,5, 09042 Monserrato, Italy

Received 30 November 2011; Accepted 11 January 2012

Academic Editor: Tai Hoon Kim

Copyright © 2012 Sofia Cosentino et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

With the aim of selecting LAB strains with antilisterial activity to be used as protective cultures to enhance the safety of dairy products, the antimicrobial properties of 117 Lactococcus lactis subsp. lactis isolated from artisanal Sardinian dairy products were evaluated, and six strains were found to produce bacteriocin-like substances. The capacity of these strains to antagonize Listeria monocytogenes during cocultivation in skimmed milk was evaluated, showing a reduction of L. monocytogenes counts of approximately 4 log units compared to the positive control after 24 h of incubation. In order for a strain to be used as bioprotective culture, it should be carefully evaluated for the presence of virulence factors, to determine what potential risks might be involved in its use. None of the strains tested was found to produce biogenic amines or to possess haemolytic activity. In addition, all strains were sensitive to clinically important antibiotics such as ampicillin, tetracycline, and vancomycin. Our results suggest that these bac+ strains could be potentially applied in cheese manufacturing to control the growth of L. monocytogenes.