Metagenomic reveals succession in the bacterial community and predicts changes in raw milk during refrigeration

In this study, metagenomics was used to analyze microbial succession and predict changes in raw milk during 6 days of storage at 4 ºC, aimed at determining how microorganisms drive the deterioration of refrigerated raw milk. The microbial community in raw milk changed significantly with an extension of refrigeration time ( P  < 0.01). The dominant bacterial genera gradually evolved from Acinetobacter, Streptococcus , and Anaplasma to Flavobacterium, Pseudomonas , and Lactococcus . KEGG annotation results indicated that the main role of the bacterial community included amino acid biosynthesis, carbon metabolism, and functioning as an ABC transporter. Additionally, lipid, amino acid and carbohydrate metabolism pathways were significantly expressed at the beginning, middle, and end of refrigeration, respectively. Refrigeration time is an important factor affecting the composition of the microbial flora in raw milk. The results of this study illustrate the role of microorganisms in the deterioration of refrigerated raw milk.