Dynamic changes in microbiota and metabolome of Kazakh cheese under traditional handicraft

Kazakh cheese is a traditional fermented dairy product. In this study, high-throughput sequencing, HS-SPME-GC-MS/MS, and untargeted metabolomics were employed to investigate the microbial succession and flavor profiles of Kazakh cheese under traditional handicraft. During processing, Lactobacillus and Acetobacter were the dominant bacterial genera, while Pichia and Kluyveromyces were the predominant yeast genera. The predominant volatile compounds identified across different stages were phenethyl alcohol, acetoin, hexanoic acid, and phenethyl acetate, with their maximum concentrations attained at the cheese during ripening (CR) stage. KEGG pathway enrichment analysis identified amino acid metabolism as the most significantly enriched pathway. Furthermore, Spearman correlation analysis revealed a significant association between Pichia, Lactobacillus, Lactococcus, Kluyveromyces, and flavor compounds, suggesting the crucial role of these microbes in flavor development. This study provides a theoretical foundation for enhancing the quality of traditional fermented Kazakh cheese and advancing Xinjiang's specialty dairy industry.