冷海水保藏下鲐鱼（Pneumatophorus japonicus）菌相变化规律及优势腐败菌的分离鉴定

Microflora Composition Variation in Mackerel (Pneumatophorus japonicas) Stored in Refrigerated Seawater, and Isolation and Identification of the Dominant Spoilage Bacteria

摘要:

以冷海水保鲜的鲐鱼为研究对象，通过选择性培养基和16S rDNA序列分析法探究其在冷海水保鲜过程中的菌相变化，确定了鲐鱼在冷海水保鲜条件下的优势腐败菌，并通过MEGA5.2软件构建了贮藏末期代表菌株的系统发育树。结果表明：冷海水保鲜鲐鱼样品在贮藏初期（第0 d）的微生物比较复杂，优势种群是假单胞菌属（Pseudomonas sp.）和嗜冷菌属（Psychrobacter sp.），还有少量的类芽孢杆菌属（Paenibacillus sp.）、希瓦氏菌属（Shewanella sp.）、蜡状芽孢杆菌（Bacillus anthracis）、枯草芽孢杆菌属（Brevibacterium sp.）；随着贮藏时间的延长，鲐鱼样品中的菌相逐渐变的单一，假单胞菌属迅速下降，希瓦氏菌属迅速增加；贮藏末期希瓦氏菌属和肠杆菌属（Enterobacter sp.）的比例迅速增加，其中希瓦氏菌属呈上升趋势且到贮藏后期数量占绝对优势，被确定为鲐鱼冷海水保鲜条件下的优势腐败菌。

Abstract:

Mackerel stored in refrigerated seawater (RSW) was studied with respect to variation in the microflora composition during storage, as analyzed by selective culture media and 16S rDNA sequence analyses. The dominant spoilage bacteria of mackerel stored with RSW were identified and a phylogenetic tree of the typical strains at the late stage of the storage period was constructed using Molecular Evolutionary Genetics Analysis (MEGA) 5.2 software. The results showed that there were complex microbial communities in the mackerel samples at the initial stage of storage, with the dominant microorganisms being Pseudomonas sp. and Psychrobacter sp., along with small proportions of Paenibacillus sp., Shewanella sp., Bacillus anthracis, and Brevibacterium sp. With extended storage time, the microflora composition gradually became uniform, as a significant decrease and an increase were observed in the proportions of Pseudomonas sp. and Shewanella sp., respectively. The proportions of Shewanella sp. and Enterobacter sp. increased rapidly at the late stage of storage. Overall, the proportion of Shewanella sp. showed an upward trend, with the corresponding viable count becoming dominant by the late stage of storage. Therefore, Shewanella sp. was determined as the dominant spoilage bacteria for mackerel stored with RSW.