Molecular characterization of spoilage microbiota in high CO2 refrigerated large yellow croaker (Larimichthys crocea) fillets using metagenomic and metabolomic approaches

Although, the negative role of microorganisms in food safety is well known, the specific role of microorganisms on food is still unclear. The effects of high concentration CO2 on the metabolism of specific spoilage organisms of large yellow croaker and the mechanism of microbial action in the spoilage process of large yellow croaker were investigated. Specific spoilage organisms of large yellow croaker in a refrigerated environment obtained by biodiversity analysis. The effects of spoilage microorganisms on fish fillets were explored using metagenomics and metabolomics approaches. The results showed that the high concentration of carbon dioxide effect prolonged the shelf life of refrigerated large yellow croaker and delayed the deterioration of its quality during storage. Meanwhile, the modified atmosphere packaging with high concentration of carbon dioxide can effectively inhibit the growth of microorganisms, change the structure of spoilage microbial flora, and affect the metabolism of spoilage microorganisms. Pseudomonas spp. and Shewanella spp. had strong spoilage potential and made important contributions to the production of biogenic amines in fish. The contribution of Shewanella spp. to fish spoilage is stronger at high CO2 concentrations. The metabolic capacity of spoilage microorganisms was altered by high CO2 concentration, and the arginine decarboxylase (ADC) pathway was the main pathway for production of putrescine under high CO2 concentration. This study contributes to a better understanding of the role of microorganisms in fish spoilage and provides useful information for the development of new preservation methods.