Insight into the heterogeneity of spoilage potential in meat-borne Serratia spp

Serratia spp. are common spoilage bacteria in meat. This study screened five Serratia strains with significant proteolytic and lipolytic activities (Serratia bozhouensis YB10, Serratia myotis YB16, Serratia quinivorans NC6, Serratia liquefaciens NC12, and Serratia grimesii NC17) from 34 meat-borne Enterobacteriaceae isolates. Their spoilage potential was evaluated by analyzing spoilage-related phenotypes and spoilage capacity in a vacuum-packaged pork model. Differences in spoilage phenotypes among strains, including proteolytic and lipolytic activities, growth characteristics, motility, extracellular polysaccharide (EPS) production, adhesion capacity, and biofilm formation, were observed and found to be regulated by temperature. The results indicated that 30 ℃ was more conducive than 37 ℃ for the growth and phenotypic expression of most Serratia strains. The motility of the strains was determined, with NC12 exhibiting the strongest motility. Comprehensive evaluation indicated that YB16 possessed relatively strong spoilage potential. It demonstrated the highest proteolytic and lipolytic activities at 37 ℃ and showed prominent adhesion capacity, EPS production, and biofilm formation at 4 ℃. In addition, it effectively degraded both sarcoplasmic and myofibrillar proteins. In the pork model, all strains colonized rapidly, significantly increasing total viable count (TVC), total volatile basic nitrogen (TVB-N), pH, and thiobarbituric acid reactive substances (TBARS) values, thereby accelerating protein and lipid deterioration. YB16 showed particularly vigorous growth and spoilage metabolism during the later storage period. These findings reveal interspecies heterogeneity in spoilage potential among Serratia strains, providing a novel theoretical basis for understanding species-specific spoilage mechanisms and offering insights for developing targeted preservation strategies to enhance meat quality and safety.