Effects of freezing-storage temperature on the shelf life of mackerel fish

The purpose of this study was to evaluate changes in the quality characteristics of mackerel fish fillet under freezing storage conditions. The changes in product quality were determined by measuring pH, volatile basic nitrogen (VBN); thiobarbituric acid (TBA), lightness (L^∗), redness (a^∗), yellowness (b^∗) values, shearing force, and microbiological evaluation (Total Plate Count, TPC) during 21 days of storage at -20, -5, and -1°C, and their shelf-lives were established. TPC as an effective quality indicator was used to estimate the shelf-life via linear regression analysis. The TPC increased steadily with increasing storage periods at every temperature (p<0.05) and showed a significant relationship with temperature at -1°C (r=0.949), -5°C (r=0.919), and -20°C (r=0.905). Therefore, based on TPC, the shelf life of the mackerel fillet was noted to be 32 days when stored at -1°C, more than 51 days when stored at -5°C, and about 2 months when stored at -20°C.