Sélection et caractérisation de souches de Carnobacterium pour la biopréservation du saumon fumé

In order to develop a biopreservation strategy in cold-smoked salmon, the inhibitory capacity of 3 bacteriocin-producing Carnobacterium strains isolated from fish have been tested towards Listeria monocytogenes strains. C. divergens V41 maintains the level of Listeria below 50 CFU/g in sterile cold-smoked salmon during the 28 days of vacuum storage at 4 and 8°C, thanks to the divercin V41 action. For its use in the product, the culture of the strain was optimized in a growth medium without animal protein. On commercial cold-smoked salmon slices, the strain inhibits slightly the endogenous microflora and doesn't modify the sensorial quality, but it produces tyramine, a biogenic amine. A non-producing tyramine mutant was obtained by chemical mutagenesis. This mutant was characterized and showed no enzymatic activity due to a stable mutation in the structural gene of tyrosine decarboxylase (1863 bp). The mutant C. divergens V41A8 has the characteristics of a good biopreservation agent.