Abstract: Freshwater prawns were packaged in trays or under modified atmosphere (MAP, 50% CO2/50% N2) and subsequently stored at 4 ℃ for up to 6 days. In order to determine the shelf life, total viable counts (TVC) and total volatile base nitrogen (TVB-N) contents were determined during the storage period. Subsequently, the microbial community diversity was evaluated by 16S rDNA amplicon sequencing. The results indicated that the shelf life under air packaging and MAP was 2 and 4 days, respectively. A considerable difference in the microbial community structure was observed between the two packaging treatments. Flavobacterium, Acinetobacter and Shewanella were dominant spoilage bacteria in air packaging, which were the main microflora resulting in shrimp decay in low temperature storage. However, the counts of Flavobacterium and Shewanella were reduced dramatically and Pseudomonas was dominant in MAP packaged prawns. MAP could inhibit the growth of the dominant spoilage bacteria in air packaging and thus extend the shelf life of chilled prawns. However, Pseudomonas became new dominant bacteria because of the strong tolerance. These results provide a theoretical basis for ensuring the quality and safety of chilled prawns.

Key words: prawn, modified atmosphere packaging, shelf life, microbial community diversity