Integration of microbial diversity and metabolite profiles reveals the effects of Staphylococcus xylosus and Staphylococcus carnosus on flavor formation in a fermented meat product model system.

This study aims to systematically elucidate the mechanisms by which Staphylococcus xylosus (S. xylosus) and Staphylococcus carnosus (S. carnosus) contribute to flavor formation in fermented meat products. By establishing a fermented meat model system, this study compared the effects of control, single inoculation, and mixed inoculation on physicochemical properties, microbial community structure, and metabolomic profiles. Findings revealed that the mixed inoculation group exhibited lower pH and water activity during the late fermentation stage. Compared to the control group, inoculation treatments significantly delayed lipid and protein oxidation processes (p < 0.05). While exogenous inoculation did not significantly alter overall bacterial diversity, it markedly increased the relative abundance of Staphylococcus species and inhibited the growth of potential spoilage bacteria such as Pseudomonas. Volatile metabolite analysis identified 33 flavor compounds. The inoculated groups showed significantly elevated total concentrations of aldehydes and ketones, with the mixed inoculation particularly enriching key flavor compounds like acetoin, 2,3-butanediol, and ethyl decanoate. Non-targeted metabolomics detected 881 non-volatile metabolites, with S. carnosus exhibiting broader metabolic regulatory capabilities than S. xylosus. Metabolic pathway analysis indicated that glycerophospholipid metabolism, purine metabolism, and lysine degradation are core pathways regulating flavor formation. This study confirms that S. xylosus and S. carnosus jointly regulate fermented meat product flavor through microbial and metabolic mechanisms, with mixed inoculation yielding superior outcomes. These findings provide a robust theoretical foundation for the precise regulation of fermented meat product quality and the development of efficient composite starter cultures.