The dynamic succession of the core microbial communities in pasteurized milk during refrigeration based on metagenomics

Abstract

The residual microorganisms in pasteurized milk undergo continuous changes during refrigeration. These microorganisms can metabolize the components of pasteurized milk, causing it to deteriorate and become inedible. The core microorganisms play a crucial role at different refrigeration stages. Using metagenomic sequencing, we analyzed the core microbial communities, succession patterns, and functional gene annotations of pasteurized milk during 14 days of refrigeration at 4 °C. The result showed that the dominant genus gradually changed from Acinetobacter to Corynebacterium in the early stage of the refrigeration period (0 - 4d), then to Pseudomonas in the middle stage (4 - 8d), and Pseudomonas became the absolute dominant genus after the following time (8 - 14d). KEGG annotation predicted that carbohydrate and amino acid metabolism were the metabolic categories with the most annotated functional pathways. CAZy annotation revealed that GHs and GTs were more annotated in the early and middle stages of refrigeration, whereas CBMs were predominantly annotated in the late and final stages (8-14d). These findings reflected potential functional shifts associated with microbial succession, laying a foundation for subsequent research on the quality and safety of pasteurized milk.