不同贮藏温度下斑点叉尾鮰鲜度及优势腐败菌群变化规律研究

Freshness and dominant spoilage flora varying patterns for Ictalurus Punctatus under the different storage temperatures

为揭示常温和低温贮藏中斑点叉尾鮰腐败菌群的构成及变化规律,研究测定了4℃和20℃贮藏中斑点叉尾鮰的鲜度指标变化,并应用高通量测序技术分析了不同时间点的菌相构成及其丰度变化。结果表明,在4℃和20℃贮藏期内鮰鱼p H值变化均呈先下降后上升趋势,挥发性盐基氮(TVB-N)、感官评分(QI)、菌落总数(TAC)呈上升趋势,其中QI、TVB-N值与TAC具有显著相关性(p<0.01)。高通量测序结果显示16个属的细菌在贮藏期内相对丰度超过0.1%,其中Pseudomonas spp.,Shewanalla spp.和Bacillus spp.在新鲜点的相对丰度分别达到20.62%、3.21%和1.25%。在20℃贮藏1 d后Pseudomonas spp.,Shewanalla spp.,Bacillus spp.,Acinetobacter spp.,Coprothermobacter spp.菌属相对丰度均超过1.0%,表明这些菌属是20℃贮藏中潜在的主要腐败菌。在4℃贮藏中Shewanalla spp.相对丰度显著上升,由3.21%(0 d)上升到45.96%(12 d),而其他菌属变化并不显著,表明Shewanalla spp.是鮰鱼4℃冷藏中主要的致腐菌群。

To reveal the spoilage flora composition and varying patterns of Ictalurus Punctatus during storage at regular and low temperature, the Ictalurus Punctatus stored at 4℃ and 20℃ were studied for their freshness and microflora constitution using conventional analysis combined with high-throughput sequencing technology. The results showed that the pH value declined first and then rose, while TVB-N, QI and TAC values kept increasing trend at all times during storage at both 4℃ and 20℃. The QI and TVB-N values correlated with the TAC value significantly （p〈0.01）. The high-throughput sequencing results showed that the relative abundance of 16 bacterial genera exceeded 0.1%, in which Pseudomonas spp. Shewanalla spp. Bacillus spp. reached to 20.62%, 3.21%, and 1.25% at the freshness point. After storage at 20℃ for 1 d, the relative abundance of Pseudomonas spp., Shewanalla spp., Bacillus spp., Acinetobacter spp., Coprothermobacter spp. were higher than 1.0%, indicating that these 5 genera were main spoilage flora for Ictalurus Punctatus at 20℃ storage. At 4℃ storage, only the relative abundance of Shewanalla spp. increased significantly, and reached to 45.96% （12 d）, while no insignificant change was observed for the other genera. The result demonstrated that Shewanalla spp. was the dominant flora causing Ictalurus Punctatus spoilage at 4℃ storage.