Abstract: In this study, metatranscriptomics was used to analyze the relationship of differential genomic transcription and metabolic pathways in microbes on the surface of chilled Tan sheep meat sealed in trays and stored for 0, 4 and 8 days with microbial community succession over the 8-day storage period. The results showed that the number of differentially expressed bacterial genes at 0, 4 and 8 days of storage were 429, 15, and 1 529, respectively. Through KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis of these DEGs, the differentially expressed genes involved in nucleotide metabolism, lipid metabolism, energy metabolism, carbohydrate metabolism and amino acid metabolism were significantly enriched, indicating that these metabolic pathways played important roles in the succession of microbial community on chilled Tan sheep meat. At the three storage periods, Proteobacteria was the dominant microorganism. Pseudomonas and Enterobacteriaceae, belonging to the Proteobacteria phylum could rapidly grow and reproduce to dominance by utilizing oxygen in the storage environment and glucose in the mutton as the carbon source. As storage proceeded, oxygen was depleted, and the pH of Tan sheep meat was reduced so that lactic acid bacteria quickly grew to be the third most microorganism after Pseudomonas and Enterobacteriaceae. The results of this study can provide a theoretical reference for predicting the microbial community and quality of Tan sheep meat and for controlling the microbial load on it during chilled storage.

Key words: Tan sheep meat; microbial communities; metatranscriptomics; metabolic process