Effects of Storage Temperature on the Microbial Flora, Odor, and Quality of Shucked Pacific Oysters Under Mimicked Commercial Shipping Conditions

The occurrence of unpleasant odors during the storage of shucked oysters shipped in brine is considered a critical issue in the improvement of oyster quality. This study focused on the storage temperature as a strategy to control odor development and assessed storage conditions at different temperatures. Analyses focused on the bacteria (total viable count and bacterial flora), biochemical induces (pH and total volatile basic nitrogen), and odor (sensory evaluation and volatile organic compounds) of oyster meat and brine. In sensory evaluation and odor sensor measurements, odor intensity remained unchanged at 0 °C but increased significantly at 3 °C. Odor generation was confirmed to be decreased at low temperatures. In addition, compared to 3 °C storage, 0 °C storage effectively suppressed the increase in viable bacterial count, the production of volatile organic compounds, the production of trimethylamine, and the decrease in pH. In particular, the proliferation of Psychrilyobacter and Psychromonas and the production of 1-propanol and short-chain fatty acids were significantly inhibited. In oyster meat, aldehyde production was significantly suppressed at 0 °C. Furthermore, total volatile basic nitrogen levels were also lower than those at 3 °C. Therefore, even a slight temperature difference contributes to improved quality, suggesting that temperature management during storage plays a crucial role in quality changes.