Bacterial changes and quality deterioration of freshwater shellfish Hyriopsis cumingii meat under different temperature storage

Hyriopsis cumingii is an important economic freshwater shellfish in China and there is a need to understand changes in the microbial community structure resulting in multidimensional quality degradation when the fish is stored at different temperatures. This study integrated 16S rRNA full-length sequencing with multidimensional quality indicators to investigate the temperature-regulated bacterial community shifts and quality deterioration mechanisms in stored H. cumingii meat. The results showed that bacterial richness (Chao1 index) decreased progressively with both refrigerated (4 °C) and room-temperature (25 °C) storage. Community composition underwent significant restructuring, with Bacteroidota decreasing at 25 °C while Bacillota increased compared to 4 °C storage. Additionally, the refrigerated group showed enrichment of Delftia turuhatensis and Chryseobacterium indologenes compared to the room-temperature storage group. Temperature significantly restructured bacterial communities, with notably higher pathogenic bacteria under refrigeration and spoilage bacteria dominance at room temperature. Metagenomic functional profiling revealed temperature-driven metabolic pathway divergence, indicating distinct spoilage mechanism. Predictable quality changes in H. cumingii correlated with temperature-imposed microbial composition.