不同包装方式下冷鲜青虾的菌群多样性分析

Microbial Community Diversity Analysis of Chilled Prawn(Macrobrachium nipponense) with Different Packaging Treatments

对青虾采用两种包装方式:托盘包装和气调包装(体积分数50%CO_2+50%N_2),在4℃条件下贮藏6 d,测定菌落总数和挥发性盐基氮含量,确定不同包装方式下青虾的货架期;随后利用16S rDNA扩增子测序对两种包装方式下青虾微生物多样性进行研究,比较其菌相变化,确定其变化规律。结果表明:托盘包装组和气调包装组的货架期分别为2 d和4 d;且两种包装方式下变质青虾的菌群结构有较大差异,在托盘包装方式下,优势菌群主要以不动杆菌、黄杆菌和希瓦氏菌为主,是普通低温贮藏时造成青虾腐败的主要菌群;采用气调包装后,黄杆菌和希瓦氏菌数量大大降低,假单胞菌成为主要优势菌群;体积分数50%CO_2+50%N_2气调包装能抑制托盘包装时优势腐败菌的增殖,从而延长货架期;而假单胞菌有较强的耐受力,成为新的优势腐败菌。研究结果为保障青虾的质量安全提供了理论依据。

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.