||Brillet-Viel Anne, Matamoros Sebastien, Blanchet-Chevrollier Christine, Leroi Francoise, Prevost Hervé, Pilet Marie-France
||Seafood research from fish to dish Quality, safety and processing of wild and farmed seafood
||edited by: J.B. Luten, C. Jacobsen, K. Bekaert, A. Saebø and J. Oehlenschläger
||salmon, Carnobacterium, biopreservation
||In this study, we have screened a colLection of Carnobacterium strains that could be used for biopreservation in order to find a natural tyramine negative strain. This screening was performed using the detection of a part of the tyrosine decarboxylase gene by PCR test. On 35 strains of Carnobacterium tested, all showed the presence of the tdc gene suggesting that they all produce tyramine. This was assessed by the quantification of tyramine production for 10 strains. In a second part, a mutation procedure using ethyl methyl sulfonate was used to select a tyramine negative mutant of Carnobacterium divergens V41 that 1S a good candidate for biopreservation applications. A mutant strain called C. divergens V41A8 was selected and characterized. The mutant was identical to the wild strain concerning carbohydrates fermentation profile, antibiogram spectrum, bacteriocin production, and bacteriocin spectrum towards Listeria monocytogenes. The growth of strain C. divergens V41A8 was tested by comparison ta the wild strain on a sterile cold smoked salmon model. The mutant grew more slowly than the wild strain on the product, but it reached nearly the same level after 28 days of storage. Moreover, the production of tyramine detected on cold smoked salmon inoculated with C. divergens V41 (122 ug/g after 28 days of storage) was not detected at all when the product was inoculated with the mutant strain C. divergens V41A8. This strain could be an interesting alternative for the application of biopreservative Carnobacterium on food products naturally contaminated with tyramine such as smoked fishes.
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|Author's final draft