In this study, a strain of lactic acid bacteria, whose cell-free supernatant (CFS) exhibited strong antibacterial activity against Vibrio parahaemolyticus, was isolated from traditional Chinese fermented vegetables and identified as Lactobacillus coryniformis 7841 (LC7841) based on morphological, biochemical, and molecular characteristics. The minimum bactericidal concentration and minimum inhibitory concentration of the 10-fold cell-free supernatant concentrate (CFSC) were both 10 μL/mL against V. parahaemolyticus. CFSC caused cell wall and membrane disruption of V. parahaemolyticus validated by the increasing leakages of intracellular substances (nucleic acids, proteins, and β-galactosidase), alkaline phosphatase and the accumulation of malondialdehyde. In further, scanning electron microscopy, transmission electron microscopy, and live-dead cell observation by confocal laser scanning microscope revealed that CFSC caused cell wall and membrane damages in V. parahaemolyticus in a concentration-dependent manner. The composite films incorporating CFSC in chitosan-gelatin based films were applied for salmon preservation. The composite films significantly inhibited the propagation of V. parahaemolyticus, decreased the decay rate, and prolonged the shelf-life of salmon. Consequently, these results indicated that CFC of LC7841 may have potential applications as biopreservatives against Vibrio-related contamination in seafood.
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