Effects of freezing history on post-thaw quality deterioration of Atlantic salmon under temperature abuse conditions

Frozen storage is widely used to preserve seafood quality. However, prior frozen storage and inadequate post-thaw temperature management can increase the susceptibility of seafood products to physicochemical deterioration. This study evaluated the combined effects of freezing history (0, 1, 5, 15, or 30 days at − 18 °C) and post-thaw storage temperature (5–15 °C) on the quality of Atlantic salmon (Salmo salar) fillets. Drip loss was greater in previously frozen samples than in non-frozen controls and was more pronounced at 15 °C than at 5 °C. TBARS values increased during post-thaw storage, indicating lipid oxidation, with faster accumulation under the 15 °C temperature-abuse condition. Texture parameters, including hardness, gumminess, and chewiness, decreased during post-thaw storage, particularly in samples with a prior frozen-storage history and elevated temperature exposure. The apparent changes in fatty acid content were interpreted as reflecting lipid hydrolysis, oxidation-related changes, and drip-associated concentration effects, rather than nutritional enhancement. Overall, the results demonstrate that freezing history can increase the susceptibility of salmon muscle to temperature-dependent physicochemical deterioration after thawing. Therefore, controlling post-thaw temperature exposure, particularly in frozen–thawed seafood products with prior frozen-storage history, is important for minimizing quality loss.