An Active Gelatin Coating Containing Eugenol and Vacuum Delays the Decay of Chinese Seabass (Lateolabrax maculatus) Fillets during Cold Storage: A Microbiome Perspective

Abstract

The purpose of this study was to evaluate the effect of an active gelatin coating containing eugenol and vacuum on the microbial diversity of Chinese seabass (Lateolabrax maculatus) during cold (−0.9 °C) storage. The bacterial sequences in Chinese seabass were observed using a high-throughput sequencing technique targeting the V3–V4 region of the 16S Ribosomal DNA (rDNA) on 0, 12th, and 24th day, which showed a more comprehensive estimate of the microbial diversity in seabass samples compared with microbial enumeration. The results revealed that the species diversity of fresh seabass was rich, mainly including Carnobacterium, Glutamicibacter, and Pseudomonas, with abundance ratios of 0.286, 0.160, and 0.130, respectively. Pseudomonas and Shewanella were the primary contaminants in the spoiled control samples, where the abundance ratios increased from 0.220 and 0.174 on the 12th day to 0.802 and 0.163 on the 24th day, respectively. Vacuum treatment could inhibit the growth of Pseudomonas and Shewanella such that when stored on the 12th day, Brochothrix became the superior genus. However, Pseudomonas and Shewanella dominated the storage until the 24th day, where their abundance ratios were 0.343 and 0.279, respectively. The inhibition of Pseudomonas and Carnobacterium was gradually enhanced with increasing concentrations of eugenol. Furthermore, an active gelatin coating containing eugenol and vacuum treatment was more effective at inhibiting the increase of the total volatile basic nitrogen. This study confirmed that an active gelatin coating containing eugenol and vacuum could reduce the species of bacteria, inhibit the growth and reproduction of the main dominant spoilage bacteria, and delay the spoilage of seabass.