Effects of anhydrous low-temperature storage on the post-capture survival, bacterial counts and meat quality of Hong Kong oyster Crassostrea hongkongensis

This study comprehensively evaluated the freshness and quality changes of Hong Kong oyster (<i>Crassostrea hongkongensis</i>) during anhydrous low-temperature storage through a multi-indicator method. The results revealed that TVB-N and MDA levels showed significant increase after nine days of storage, while pH and surface color remained stable. The counts of <i>Escherichia coli</i>, <i>Vibrio parahaemolyticus</i>, and <i>V. vulnificus</i> peaked on day three before declining, contrasting with the continuous proliferation of anaerobic lactic acid bacteria. The crude protein, total lipid, phospholipid and fatty acid contents decreased significantly with prolonged storage, while glycogen content exhibited a biphasic trend, and triglyceride levels consistently increased. Most non-volatile compounds peaked at three to six days of storage, whereas lactic acid levels progressively increased. Among volatile compounds, aldehydes were the most abundant, with hexanal levels remaining stable and 2,4-heptadienal significantly increasing by day six. In conclusion, the optimal shelf life for Hong Kong oysters under anhydrous low-temperature storage conditions should be not exceed six days.