Combined Analysis of Microbial Diversity, Water Migration, and Volatile Spoilage Profile Changes in Modified Atmosphere Packaged Crucian Carp (Carassius auratus) Fillets During Cold Storage

Microbial activity drives rapid spoilage of fish during cold storage. This study evaluated the effects of modified atmosphere packaging (MAP) on the quality parameters, volatile profile changes, and microbial diversity in crucian carp ( Carassius auratus ) fillets during cold storage. Crucian carp fillets were packaged under air packaging (CK), vacuum packaging (VP), MAP1 (60 % CO 2 /35 % N 2 /5 % O 2 ), MAP2 (35 % CO 2 /60 % N 2 /5 % O 2 ), MAP3 (60 % CO 2 /30 % N 2 /10 % O 2 ), followed by storage at 4 °C. MAP treatments significantly inhibited microbial growth. Microbial community analysis revealed dominance of Carnobacterium , Brochothrix , and Lactococcus in VP and MAP groups. Pseudomonas abundance showed strong atmosphere-dependence, reaching 52.31 % in CK but remaining negligible in MAP treated samples. Quality indices confirmed MAP treatment effectively prolonged the shelf life of fillets. Volatile profile changes identified three spoilage markers (1-butanol, 1-hydroxy-2-propanone, and 2,2,4,6,6-pentamethylheptane) that accumulated differentially of all groups at the end of storage. The content of 1-hydroxy-2-propanone in the VP and MAP1 groups was relatively low, indicating that the flavor deterioration of crucian carp in these two groups was relatively small.