Inhibitory effect and mechanism of intense pulsed light combined with ε-polylysine on Vibrio parahaemolyticus in scallops (Chlamys farreri)

Abstract

The global prevalence of Vibrio parahaemolyticus poses a significant risk for foodborne illnesses. To enhance aquatic food safety, this study investigated the microbial control efficacy of intense pulsed light (IPL) combined with ε-Poly-L-lysine (εPL) treatment on refrigerated scallops (Chlamys farreri). The εPL-IPL composite treatment extended the shelf life of scallops by 6 d and 2 d compared to the control group and the εPL-treated group, respectively, in simulated microbial contamination experiments. Electron microscopy results demonstrated that, in comparison to εPL treatment alone, the combined IPL treatment resulted in more extensive cell membrane damage and a significantly increased intracellular leakage (p < 0.05). Correlation analysis showed an extensive connection between cytoplasmic membrane disruption and the oxidative damage. After εPL-IPL composite treatment, high concentration of reactive oxygen species was detected in V. parahaemolyticus intracellularly, and the lipid peroxidation level was increased by 6.70-fold relative to the control group and by 3.07-fold relative to the εPL group. Meanwhile, three major antioxidant enzymes, Catalase (CAT), Superoxide Dismutase (SOD), and Glutathione Peroxidase (GPx), showed decreases in activity of 84.23 %, 32.71 %, and 96.34 %, respectively. Our results indicate that superimposed 1200 J/pulse IPL applied for 10 cycles reduces εPL addition by 85 % and effectively inactivates microorganisms through a synergistic mechanism where IPL disrupts cellular integrity and facilitates εPL translocation, while their combined effects induce oxidative stress, suppress antioxidant defenses, and damage cellular membranes. The εPL-IPL composite treatment holds great promise as a strategy to reduce the use of preservatives and achieve enhanced inactivation, thereby effectively combating bacteria and preserving aquatic food.