Inhibition of Listeria monocytogenes in cold-smoked salmon by Carnobacterium piscicola CS526 isolated from frozen surimi

Abstract

Strain CS526 was isolated from frozen surimi and identified as a bacteriocin producer that had strong inhibitory activity against Listeria monocytogenes. Strain CS526 was identified as Carnobacterium piscicola by partial 16S rDNA sequence similarity. The ability of this bacteriocinogenic strain and nonbacteriocinogenic C. piscicola JCM5348 to inhibit the growth of L. monocytogenes was examined in culture broth incubated at 12°C and cold-smoked salmon stored at 4, 12, and 20°C. L. monocytogenes viable counts in the culture broth rapidly declined from 106 colony-forming units per ml to less than 10 colony-forming units per ml within 1 day at 12°C in the presence of C. piscicola CS526. At 4 and 12°C, inhibition of L. monocytogenes on salmon depended on the initial inoculum level of C. piscicola CS526. However, C. piscicola CS526 was bactericidal to L. monocytogenes within 21 and 12 days at 4 and 12°C in cold-smoked salmon, respectively, even when the initial inoculum levels were low. C. piscicola CS526 suppressed the maximum cell number of L. monocytogenes by two and three log cycles, even at 20°C. However, C. piscicola JCM5348 did not prevent the growth of the pathogen, except at 4°C. Bacteriocin was detected in the samples coinoculated with C. piscicola CS526. The study shows that C. piscicola CS526 might have potential for biopreservation of refrigerated foods against L. monocytogenes.