Microbial Succession Pattern and Spoilage Potential of Specific Spoilage Bacteria in Refrigerated Monopterus albus

To investigate the microbial succession and the spoilage potential of specific spoilage organisms (SSOs) in refrigerated Monopterus albus at 4 ℃, Illumina high-throughput sequencing was employed to analyze the diversity and dynamic shifts in microbial communities. Traditional selective culture methods were utilized to isolate and identify SSOs, and their spoilage potential was assessed by comparing the yield factor of spoilage metabolites (Y_(TVB-N/CFU)). The results indicated that before storage (day 0), the microbial richness and diversity were the highest, with the relative abundance of Streptococcus (31.56%), Gemella (11.69%), Salinivibrio (7.5%), and Burkholderia-Caballeronia-Paraburkholderia (5.46%) being greater than 5%. During the middle and late stages of storage (≥ 15 days), Vagococcus, Acinetobacter, Burkholderia-Caballeronia-Paraburkholderia, and Psychrobacter emerged as the dominant genera. Linear discriminant analysis effect size (LEfSe) analysis revealed that the marker genera showing significant differences between before storage and after storage for ≥ 15 days were primarily Streptococcus, Gemella, and Salinivibrio, Vagococcus, Acinetobacter, and Psychrobacter. Six SSOs were isolated from the 30-day stored sample, namely Pseudomonas fluorescens, Bacillus cereus, P. putida, Acinetobacter johnsonii, Lactococcus raffinolactis, and Carnobacterium divergens. The decreasing order of the Y_(TVB-N/CFU) values of these SSOs was P. fluorescens (41.18 mg/CFU) > B. cereus (29.70 mg/CFU) > L. raffinolactis (15.07 mg/CFU) > A. johnsonii (14.59 mg/CFU) > P. putida (8.22 mg/CFU) > C. divergens (4.61 mg/CFU). This study provides a theoretical foundation for the development of efficient low-temperature preservation technologies for M. albus.