Quality changes of Jinga shrimp (Metapenaeus affinis) during delayed storage in ice

The present study, investigated the effect of delayed ice storage on the quality and shelf-life of Jinga shrimp (Metapenaeus affinis) during a period of 18 days. Freshly captured shrimps were divided into three groups. The first group was kept in ice immediately, while the second and third groups were mixed and covered with ice one hour, and two hours after capture respectively. The shelf-life of each group was determined using microbial (total number of mesophilic and psychrophilic bacteria), chemical (pH, Total Volatile Bases Nitrogen ‘TVB-N’ and Thiobarbituric Acid ‘TBA’) and sensory indices. The results of microbial counts showed that the least bacterial growth occurred in the first group, preserved in ice immediately after the catch (P < 0.05). Among the chemical parameters the highest increase in pH, TVB-N and TBA was observed in the third group, preserved in ice with two hours delay. The outcome of the sensory evaluation revealed that the shelf-life of the first group of shrimps constantly stored in ice was 12 days while those of the second and third groups kept in ice with one and two hours delay after capture decreased to 10 and 8 days respectively. In most days of this study, there was a high correlation between sensory, microbial and chemical indices. The results of sensorial, microbial and chemical tests of the treatments indicate that every hour of time-lag in ice-storage of freshly captured Jinga shrimp will reduce its shelf-life by about two days compared to the samples iced immediately after catch.