Quality evaluation of tray-packed tilapia fillets stored at 0 °C based on sensory, microbiological, biochemical and physical attributes

The quality deterioration of tray-packed tilapia (genetically improved farmed tilapia strain of Oreochromis niloticus) fillets stored at 0 degrees C were studied by integrated evaluations of sensory, microbiological, biochemical and physical analysis, in order to expound the mechanism of fish spoilage and develop the most reliable indicators for quality assessment. The results showed that four quality index as Pseudomonas counts, total volatile basic nitrogen (TVBN), cadaverine (CAD) and K value were highly correlated (r > 0.90) with storage time and sensory acceptability. Protein degradation was visible on SDS-PAGE when microbiological load exceeded 6 log cfu/g. Thiobarbituric acid reactive substances (TBARS) value remained at a very low level throughout the storage, suggesting low lipid oxidation in muscle. Hardness decrease tested by texture machine was consistent with texture softening of fillets in the sensory evaluation. Considering fish freshness and microbiological safety, the shelf life of tilapia fillets stored at 0 degrees C was approximately 10 - 12 days.