Impact of antimicrobials, naturally produced by lactic acid bacteria, on the Listeria monocytogenes growth in minced salmon

The effect of antimicrobials produced by lactic acid bacteria (LAB) on the inhibition of Listeria monocytogenes ATCC 19111 in minced salmon was analysed and compared to the sodium lactate and bacteriophage action during storage at 6 degrees C. All tested additives showed a quite noticeable reduction of L. monocytogenes counts by 30-95% compared with control samples. Antimicrobials produced by the tested Enterococcus faecium strains showed moderate inhibitory activity while the greatest inhibitory activity was observed for antimicrobials produced by Streptococcus thermophilus 43 directly in the same way as the additive sodium lactate. The correlation was determined within inhibitory efficiency and produced total fatty acid amounts. S. thermophilus 43 showed the exceptionally stronger inhibition index for L. monocytogenes and yielded the higher monounsaturated fatty acid amount (42%) than E. faecium strains. Both E. faecium strains showing the lower inhibition efficiency produced the highest polyunsaturated fatty acid amounts (21.7-29.5%). E. faecium L41-2B-2v and S. thermophilus 43 were found to produce bioactive compounds like omega-3 and omega-6 FAs.