Frozen kinetics models for sensory, chemical, and microbial spoilage of preserved razor clam (Sinonovacula constricta) at different temperatures

Refrigerated treatment offers an effective avenue to delay spoilage process of aquatic products during storage, while none or less study has been reported for bivalve species. This work aims to investigate the variations in different storage freshness of frozen razor clam samples, by which an effective evaluation system based on frozen kinetics models was established. In this study, fresh razor clam samples were preserved at the temperature of 268, 258, and 248 K for 40 days, respectively. The spoilage process was determined by a series of freshness assays, including sensory score (SS), electric conduction (EC), total volatile basic nitrogen (TVB-N), K-value, and total colonies counts (TCC). On this basis, the variations in these indexes were fitted by zero-, first- and second- order kinetic models. Results showed that zero -order kinetic model was more suitable to fit each freshness trend. Accordingly, the shelf life of razor clam was predicted as 47 similar to 54, 79 similar to 84, and 121 similar to 154 days when the samples were preserved at 268, 258, and 248 K, respectively. This study revealed the general trends of the frozen decay process of bivalve species, which is instructive to establish applicative models for the real distribution chain.