Inactivation of Listeria monocytogenes and natural microbiota on raw salmon fillets using acidic electrolyzed water, ultraviolet light or/and ultrasounds

Abstract

The objective of this study was to investigate the effectiveness of various decontamination treatments of raw salmon fillets, namely acidic electrolyzed water (AEW), ultraviolet light (UV), ultrasound (US), and their combinations against Listeria monocytogenes and natural microbiota including total viable count (TVC), total coliforms, Escherichia coli, and yeasts and molds. The changes in quality and sensory parameters of treated salmon samples were also evaluated. The combined treatments: UV + US and UV + US + AEW showed significantly (P ≤ 0.05) higher reduction in L. monocytogenes of 0.79 and 0.75 log CFU/g, respectively, compared to control (0.17 log CFU/g) washed with sterile distilled water (dH2O). TVC was reduced by 0.59 and 0.64 log CFU/g after UV + US and UV + US + AEW treatments, respectively. The color and odor of salmon were significantly affected after combined treatments, but the texture and firmness of tissue were not significantly (P > 0.05) changed. These results indicate that UV + US and UV + US + AEW were the most effective at reducing the populations of L. monocytogenes and natural microbiota on raw salmon fillets. The AEW treatment by itself was found to be ineffective for raw salmon sanitation. However, these combined treatments should be improved by optimizing other factors such as treatment temperature, time and the distance between UV and food sample to enhance their anti-listerial or antimicrobial effects.