Biodiversity of Listeria monocytogenes sensitivity to bacteriocin-producing Carnobacterium strains and application in sterile cold-smoked salmon.

Abstract

The aim of this study was to demonstrate the inhibitory capacity of Carnobacterium strains against a collection of Listeria monocytogenes strains in cold-smoked salmon (CSS). Three bacteriocin-producing strains, Carnobacterium divergens V41, C. piscicola V1 and C. piscicola SF668, were screened for their antilisterial activity against a collection of 57 L. monocytogenes strains selected from the French smoked salmon industry, using an agar spot test. All the Listeria strains were inhibited but three different groups could be distinguished differing in sensitivity to the three Carnobacterium strains. However, C. divergens V41 always had the highest inhibitory effect. The antilisterial capacity was then tested in sterile CSS blocks co-inoculated with Carnobacterium spp. and mixtures of L. monocytogenes strains. C. divergens V41 was the most efficient strain, maintaining the level of L. monocytogenes at <50 CFU g(-1) during the 4 weeks of vacuum storage at 4 and 8 degrees C, whatever the sensitivity of the set of L. monocytogenes strains. C. divergens V41 may be a good candidate for biopreservation in CSS. A biopreservation strategy for CSS against the risk of L. monocytogenes was investigated using bacteriocin-producing lactic acid bacteria.