Bacterial changes and quality deterioration of freshwater shellfish <i>Hyriopsis cumingii</i> meat under different temperature storage

<i>Hyriopsis cumingii</i> 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 <i>H. cumingii</i> 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 <i>Delftia turuhatensis</i> and <i>Chryseobacterium indologenes</i> 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 <i>H. cumingii</i> correlated with temperature-imposed microbial composition.