Impact of Different Starter Cultures on the Microbial Community and Volatile Flavor Compounds in Xuanwei Ham: A Metagenomic and GC-MS Analysis

Despite growing knowledge of the individual roles of Staphylococcus saprophyticus and Meyerozyma guilliermondii in dry-cured meat fermentation, their synergistic use as composite starter cultures in traditional ham production has remained unexplored. In this study, we developed a mixed starter culture using S. saprophyticus and M. guilliermondii isolated from naturally fermented Xuanwei ham and systematically evaluated its effects on ham maturation. Inoculation with the composite culture significantly enhanced both the diversity and concentration of volatile compounds, with 96 volatile flavor compounds associated with ham flavor identified in total. This group also exhibited markedly improved physicochemical parameters, including peroxide value, moisture content, thiobarbituric acid (TBA) value, color, and texture. Metagenomic sequencing further revealed that the composite starter reshaped microbial community structure and metabolism, thereby promoting flavor compound formation. Collectively, these findings demonstrate that the composite culture not only shortens fermentation time but also improves the overall quality of Xuanwei ham, providing a scientific basis for the development and application of novel mixed starter cultures in dry-cured ham production.