Abstract: The study focused on the lightly preserved cooked mackerel and compared the quality characteristics of cooked mackerel and raw mackerel. Quality changes and safety of cooked mackerel were analyzed during commercial sterilization storage. The spoilage bacteria causing the swollen bag were identified by Biolog and 16srDNA gene sequencing. The results showed that the salt content and pH of the mackerel increased significantly after processing, and the water content, Aw and total viable counts（TVC）decreased significantly. The sensory evaluation results of odor, appearance, elasticity and taste were not significant at the initial and end point of commercial sterilization storage of cooked mackerel (P>0.05). The TVC of cooked mackerel at the initial point (A0) and end point (A1) were less than 2（lg（CFU/g））. The TVC of the swollen bag samples (B1, B2, B3 and B4) during commercial sterilization storage was from 4（lg（CFU/g））to 6（lg（CFU/g））, and they exceeded the safety value. Bacillus licheniformis, Bacillus subtilis, Bacillus sonorensis and Brevibacterium sp. were isolated from the swollen bag samples. The pH of A0 and A1 were higher than B1, B2, B3 and B4 during storage. The pH of A0, A1 and B1~B3 showed a downward trend, and only B4 increased lightly. The difference of TVBN values between the swollen bag sample（except B2）and the unswollen bag sample was significant (P <0.05). From the beginning to the end of the commercial sterilization storage, the histamine content of cooked mackerel was lower than the detection limit (5 mg/100 g). This study can provide support for the optimization of lightly cooked mackerel products to control product quality and safety.

Key words: lightly preserved cooked-mackerel, quality characteristics, residual bacteria, histamine