Comparative Evaluation of Shelf Life and Quality of Freshwater Fish Species, Wallago attu at Different Duration of Low Temperature Preservation

A study was conducted to evaluate the shelf life and quality of the fish at different duration of low temperature preservation. The fish was subjected to sensory evaluation to assess the shelf life and later biochemical and microbial analysis was carried out at an interval of 24 hours upto 96 hours of storage duration. Results of sensory evaluation showed that the fish had an acceptable value of 8.56±0.23 in fresh condition, which slightly changes to 8.5±0.00, 8.1±0.34, 7.8±0.45 and 7.4±0.23 in 24, 48, 72 and 96 hours of storage respectively. Total volatile basic nitrogen (TVBN) analysis showed an increase level from 4.32±0.05 in fresh to 4.34±0.02 with increase in storage duration upto 96 hours without any significant change. The vitamin analysis showed a decreasing trend for storage samples. Among all the fat soluble vitamins, fresh sample showed the highest value for vitamin A which is 62.41±0.5 and lowest value 1.16±0.06 was found for vitamin E. Vitamins showed significant decrease in content during storage. The microbial analysis for Total Plate Count (TPC) increased gradually from 2.38±0.22 in fresh to 2.90±0.51 in 96 hours of storage duration without showing any significant difference. However both Escherichia coli (EC) and Coliform Count (CC) were found absent in both fresh and storage samples. The results of the study showed that, the sensory characteristics, TVBN and microbial count of the fish remains significantly unchanged upto 96 hours of storage. However, results of vitamins showed that Vitamin A and D significantly changed at the end of storage duration while vitamin E and K remain significantly unchanged during the overall storage period. Thus, the biochemical and microbial analysis stated that the preserved fish samples are healthy for human consumption but upto a specific storage period. Overall, it is well recommended to consume fish in fresh condition and for stored fish, not more than 96 hours in the refrigerator in order to preserve the better quality and more benefits for human health.