6533b7cffe1ef96bd12585c3

RESEARCH PRODUCT

Anti-Listeria activity of lactic acid bacteria in two traditional Sicilian cheeses

subject

description

<em>Listeria monocytogenes</em> is a pathogen frequently found in dairy products, and its growth is difficult to control. Bacteriocinlike inhibitory substances (BLIS), produced by lactic acid bacteria (LAB), having proven <em>in vitro</em> anti-<em>Listeria</em> activity, could provide an innovative approach to control <em>L. monocytogenes</em>; however, this application needs to be evaluated <em>in vivo</em>. In this study, twenty LAB strains isolated from different Sicilian dairy environments were tested for control of growth of <em>L. monocytogenes</em> in three different experimental trials. First, raw and UHT milk were inoculated with LAB strains alone, and LAB strains mixed with <em>L. monocytogenes</em>. Second, mini-cheeses containing LAB and/or <em>L. monocytogenes</em> were produced. Third, two traditional Sicilian cheeses inoculated with a multi-strain LAB mixture combined with <em>L. monocytogenes</em> were produced. The addition of BLIS produced by LAB to milk and in mini-cheese production was unable to inhibit the growth of <em>L. monocytogenes</em>. However, an anti-<em>Listeria</em> effect was observed in the <em>Pecorino Siciliano</em> cheeses, where, after 15 days of ripening, the cheeses with added LAB had fewer <em>L. monocytogenes</em> compared to the control cheeses with no added LAB, while in the <em>Vastedda della valle del Belìce</em> cheeses, the multi-strain LAB mixture completely prevented the growth of <em>L. monocytogenes</em>.