Effect of different storage conditions on quality of White-Scar oyster (Crassostrea belcheri)

Changes in some chemical, microbiological and sensory qualities of white-scar oyster (Crassostrea belcheri) during different storage conditions were studied. Lower changes in chemical and microbiological qualities were found in chilled shell-on oysters when compared with those stored at ambient temperature. Shell-on oyster packed in 2.5% brine showed a slower decrease in pH but increased in total volatile basic nitrogen (TVB-N), total viable count (TVC) and psychrotrophic bacteria at a faster rate than those stored in air. Escherichia coli and Vibrio parahaemolyticus were less than 1.8 and 3 MPN/g, respectively. Irrespective of packing medium and storage temperature, sensory scores for every parameter decreased while microorganisms increased with the storage duration. Therefore, with respect to microbiological and sensory qualities, shell-on oyster kept in air at chilled temperature was the suggested condition to extend the acceptable quality up to 9 days. Shucked oyster packed in 4% brine showed a decrease in pH and increases in TVB-N, TVC and psychrotroph at a slower rate than those packed in 2.5% brine and water. Whereas E. coli and V. parahaemolyticus were less than 1.8 and 3 MPN/g, respectively in every packing medium and stored at chilled temperature for 12 days. The decreased in sensory score of all attributes with the increase in TVC was found in shucked oyster packed in different salt concentrations. Shucked oyster kept in 4% brine at chilled temperature was recommended up to 10 days storage.