Lactic acid bacteria biodiversity in Italian marinated seafood salad and their interactions on the growth of Listeria monocytogenes

The aim of this research was to study the biodiversity of lactic acid bacteria (LAB) in marinated seafood salad (pH 5.0) and their interaction on the growth of Listeria monocytogenes. LAB were highly present in the samples considered in this study, reaching values of 8.0 log cfu/g at the end of product’s shelf-life. A high biodiversity in terms of LAB species and strains was detected by means of RAPD–PCR within the 171 bacterial isolates collected. Among them Lactobacillus curvatus, Lactobacillus sanfranciscensis and Enterococcus were present in all the salad batches considered. Three challenge tests against L. monocytogenes were carried out in order to assess the growth of this pathogen in the presence of dominant populations of LAB. L. monocytogenes tended to decrease in time, suggesting that a stable concentration of LAB inhibits the development of this pathogenic micro-organism.