Anti‐Listerial inhibitory lactic acid bacteria in fresh farmed sea bass (Dicentrarchus labrax) fillets during storage at 4 °C under vacuum‐packed conditions

Abstract

AbstractThe inhibition capacity of four combinations of three lactic acid bacteria (LAB) (Lactococcus lactis, Lactobacillus plantarum and Carnobacterium piscicola) has been demonstrated against Listeria monocytogenes in fresh farmed sea bass fillets artificially contaminated. The four combinations gave promising results, having a significant bacteriostatic effect against all tested microflora, during 21 days of vacuum storage at 4 °C.Throughout storage, biochemical alteration appeared more pronounced in farmed sea bass fillets inoculated with pure Listeria, with significantly higher levels of total volatile bases (TVB‐N) and trimethylamine (TMA‐N). Moreover, the inoculation of LAB combinations was efficient in preventing the decrease of lipid and protein contents and preserving a good content of ω‐3 fatty acids, particularly the eicosapentaenoic acid (C20:5N3) and docosahexaenoic acid (C22:6N3).Besides, the proteolytic activity on sarcoplasmic proteins (SP) and myofibrillar proteins (MP) was determined by Sodium dodecyl sulphate–poly‐acrylamide gel electrophoresis, comparing the protein profile of control fish fillets with those inoculated with LAB strains or/and L. monocytogenes, during vacuum refrigerated storage.Practical ApplicationsDue to the increase of interest in food‐grade preservatives of biological origin, food preservation became a challenge since several foodborne pathogens pose a health risk to consumers and cause serious hazard in food products. Listeria monocytogenes is an important food poisoning pathogen that can survive in lightly preserved seafood products stored at low temperatures. Considering this, biopreservation of fresh farmed sea bass (Dicentrarchus labrax) fillets during 21 days of vacuum storage at 4 °C using four combinations of LAB strains originating from fresh seafood and having important antagonistic effect, and low proteolytic and lipolytic activities, is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes without changing the quality of the product and to guarantee adequate product safety.