Preservative effect of slightly acid electrolysed water ice generated by the developed sanitising unit on shrimp (Penaeus vannamei) - Yang Lab

Ice is widely used for the preservation of perishable seafood but not much effective in killing bacteria. Herein, in this study, we aimed to investigate the effect of slightly acid electrolysed water (SAEW) ice on the microbial spoilage together with the quality parameters to elucidate the underlying preservative mechanism. The results indicated that SAEW ice exhibited inhibitory activity toward polyphenol oxidase (PPO) and acid phosphatase (ACP) with 55.3% and 61.9% reduction of activity at day 7, respectively, along with less discolouration and the lowest K-value of shrimp. Besides, the growth of aerobic mesophilic and psychrotrophic bacteria was retarded by SAEW ice treatment (2.4 and 0.4 log CFU/g reduction, respectively). 16S rDNA-based Illumina sequencing elucidated that SAEW ice efficiently retarded the growth of Proteobacteria. Specifically, the growth of major spoilage genus presented in tap water (TW) ice treated shrimp (Shewanella, Vibrio, and Aeromonas) and NaCl ice treated shrimp (Psychrobacter) was inhibited in SAEW ice treated shrimp, which further led to the smallest increase of putrescine and cadaverine, together with the lowest values of pH and TVB-N during storage. The sensory results indicated that SAEW treatment maintained the quality of shrimp during storage in terms of colour, appearance, and texture. Overall, the SAEW ice exhibited a promising preservative effect on shrimp