Comprehensive insights into the evolution of microbiological and metabolic characteristics of the fat portion during the processing of traditional Chinese bacon

Both lean meat and fat together contribute to the consumer impression of traditional Chinese bacon. The quality of this meat product is mainly dependent on numerous biochemical reactions and microbes. For the first time, this study reveals the microbial community succession and metabolic characteristics of the fat portion during the processing of traditional Chinese bacon by high-throughput sequencing and untargeted metabolomics (ultra-high performance liquid chromatography, UHPLC). The results showed that Proteobacteria and Firmicutes were the predominant bacterial phyla in traditional Chinese bacon. At the genus level, 15 core genera (relative abundance >1%) were identified, including Salinivibrio, Staphylococcus, Brochothrix, Vibrio, Psychrobacter, Acinetobacter, Carnobacterium, Aeromonas, Pseudomona, Cobetia, Macrococcus, Enterobacter, Kocuria, unclassified-f-Vibrionaceae, and Empedobacter. Distinct separation between different groups were identified by principal component analysis, revealing significant differences in the metabolic characteristics of different samples. A total of 262 metabolites were identified, and most of the metabolites belonged to lipids and lipid-like molecules, of which 60 were identified as differential metabolites. Results of correlation analysis indicated that some differential metabolites were significantly positively correlated with dominant bacteria, such as Salinivibrio, Vibrio, Cobetia and Staphylococcus, which reinforced the fact that microorganisms have an indispensable role in the quality formation of traditional Chinese bacon.