From the isolation of bacteriocinogenic LAB strains to the application for fish paste biopreservation

Abstract

The aims were to isolate, characterize and quantifylactic acid bacteria?s (LAB) antimicrobial activity, and evaluate their application on fish paste. One hundred and thirty two LAB were isolated from mussels of the Argentine coast. From all, 22 LAB isolated which?s cell-free supernatant (CFS) presented activity against Listeria innocua and Lactobacillus plantarum were identified as Enterococcus mundtii by biochemical tests and 16S rDNA gene phylogenetic analyses. None of selected strains presented virulence factors. All of them presented the gene that codifies either for mundticin KS, or for mundticin KS and enterocin L50A. Their CFS showed activity against Gram positive bacteria. The interaction among binary mixtures of CFS was assessed against L. innocua, and an additive response was observed. The strain E. mundtii STw38 was selected because of its high capacity to grow and produce bacteriocins at refrigeration temperatures. It was applied as a protective culture to fish paste stored at 4°C. In a first stage fish paste-systems were air-packed, and then, vacuum-packed. In both cases, E. mundtii STw38 survived storage conditions and succeeded in reducing the development of native flora of fish paste. Results suggest that E. mundtii STw38 is a promising strain to be used for fish biopreservation.