Effects of gaseous ozone treatment on the quality and microbial community of salmon (Salmo salar) during cold storage

To elucidate the effect of gaseous ozone with different dose and exposing time (A and B: 1 mg/m3 or 3 mg/m3 for 5 min; C and D: 1 or 3 mg/m3 for 10 min, respectively, corona discharge method) on the quality of salmon, the microbial growth, lipid oxidation, color, odor characteristics, microbiota, and the correlations between them were studied. The results showed that the total viable counts of groups C (6.05 log CFU/g) and D (5.71 log CFU/g) were lower than the control (7.08 log CFU/g) on day 10. The ozone treatment also retarded the increase of total volatile basic nitrogen (TVB-N), thiobarbituric acid substances (TBARS), and drip losses as well as the decrease of sensory scores. Though the ozonated treatment led to a slight decrease of a* value, it could deodorize the fishy smell. The results of next-generation sequencing showed that the relative abundance of Photobacterium decreased after treatments, but recovered during storage, and it was the predominant bacteria causing the deterioration of salmon fillets according to the correlation analysis with sensory score, TVB-N, and TBARS values. The results demonstrated that gaseous ozone was a promising method for salmon preservation, and the exposing time had a greater effect on the salmon quality than the ozone concentrations in this study. The ozonation treatment with the dose of 1 or 3 mg/m3 for 10 min was recommended for salmon fillets.