Unveiling the correlations between benzoic acid content, key microbial genera, and metabolites during the storage and transportation of raw yak milk based on multi-omics analysis

Unique transport conditions in Tibetan regions delay the storage of yak milk, particularly during the July–August peak production period at 18 °C, promoting microbial activity and benzoic acid accumulation. This substantially heightens food safety risks associated with consumption. This study used 16S high-throughput sequencing and non-targeted metabolomics to examine the association between benzoic acid content, dominant bacterial genera, and key metabolites. At 0 h of storage (G0), the dominant genera in yak milk were Kaistella , Lactococcus , and Streptococcus . As storage extended to 12 h (G12) and 24 h (G24), Lactococcus emerged as the dominant genus and the key lactic acid bacterium producing endogenous benzoic acid. Metabolomics identified 729 differentially expressed metabolites. Amino acid metabolism is the primary enriched pathway. Myosmine, L-Methionine, L-Phenylalanine, 3-Isochromanone, and Indoline showed strong correlations with Lactococcus . This study provides a theoretical foundation for improving quality control and safety in yak milk production. • At 18 °C, Kaistella dominated at 0 h, succeeded by Lactococcus by 12–24 h. • Lactococcus converted hippuric acid to endogenous benzoic acid in yak milk. • Five Lactococcus -correlated metabolites signaled milk deterioration. • Amino acid metabolism was predominantly enriched.