Abstract: In order to investigate the relationship between the diversity of the bacterial community in solid-fermented fish products and their quality, bacterial numbers in four samples of traditional fermented fish produced by different procedures were examined by conventional count methods, and the structure and composition of the bacterial community were investigated by 16S DNA V4 region sequence and phylogenetic relationship analysis using Illumina HiSeq sequencing platform. Meanwhile, these samples were subjected to sensory evaluation and GC-MS analysis. The results obtained were as follows. The average number of sequences obtained from the sample was 59 250. A total of 1 053, 392, 428 and 498 operational taxonomic units (OTU) were observed for the samples zyA2, zyA5, zyB and zyC, respectively. The overall bacterial composition of the four samples was rather complicated, including more than 30 genera in 11 phyla，among which, Firmicutes was absolutely dominant, accounting for 66.25%–97.40% of the total number, followed by Proteobacteria and Bacteroides, and the main dominant genera were Staphylococcus, Enterococcus, Lactobacillus and Weissella. Compared to traditional methods, the information about bacterial community diversity provided by MiSeq sequencing was closer to the microflora in the samples. We found that there were diversities in the abundance of bacterial species in each sample and the microfloral composition was closely related to the production process. The species and quantity of bacteria also affected the color and flavor of the product. In addition, we also detected a small amount of potentially harmful spoilage organisms like Pseudoalteromonas, Tenacibaculum, Corynebacterium and Psychrobacter and conditional pathogens in the samples. Therefore, the processing conditions must be strictly controlled under the existing mode of production to avoid food safety problems.

Key words: solid-fermented fish, high-throughput sequencing, bacterial community diversity, volatile flavor compound, quality