冷藏卵形鲳鲹优势腐败菌的分离鉴定及致腐能力分析

Isolation and Identification of Dominant Spoilage Bacteria in Trachinotus ovatus during Chilled Storage and Their Spoilage Capability

为研究卵形鲳鲹冷藏末期的优势腐败菌及其致腐能力,采用传统选择性培养结合16S rDNA序列分析法,对卵形鲳鲹4℃贮藏期间腐败菌分别进行分离纯化、菌相分析及菌属确定,并以腐败物质的产量因子Y TVB-N/CFU为评价标准,定量分析了贮藏末期优势菌的致腐能力。结果得出,卵形鲳鲹4℃贮藏过程中共分离纯化出16株细菌,其中革兰氏阴性菌10株,革兰氏阳性菌6株,其分属6个菌属。贮藏初期(0 d)时菌相丰富,希瓦氏菌属(Shewanella sp.)、假单胞菌属(Pseudomonas sp.)、葡萄球菌属(Staphylococcus sp.)、芽孢杆菌属(Bacillus sp.)、乳酸杆菌属(Lactobacillus sp.)与肠杆菌属(Enterobacter sp.)等均有出现;中期(3 d)菌群种类有所减少,以希瓦氏菌属(Shewanella sp.)与假单胞菌属(Pseudomonas sp.)所占比例较高,后期(6 d)种类进一步减少,只有3株菌占较高,分别是2号腐败希瓦氏菌(Shewanella putrefaciens 48%)、5号奥奈达希瓦氏菌(Shewanella oneidensis 26.6%)与16号霍氏肠杆菌(Enterobacter hormaechei 19.4%);致腐能力由高至低依次为腐败希瓦氏菌>奥奈达希瓦氏菌>霍氏肠杆菌,其中腐败希瓦式菌致腐能力显著强于另两株菌;综合贮藏末期所占比例及致腐能力结果,最终确定腐败希瓦氏菌为4℃贮藏下卵形鲳鲹的优势腐败菌。

In order to study the dominant spoilage bacteria and their spoilage capability of Trachinotus ovatus fillets at the end of chilled storage,traditional selective medium method and 16S rDNA sequence analysis method were taken to isolate,purify,analyze and determine the spoilage bacteria in Trachinotus ovatus during chilled storage.The spoilage capability of dominant spoilage bacteria at the end of storage was quantitatively analyzed by Y TVB-N/CFU.The results showed that 16 strains of bacteria(10 Gram-negative strains and 6 Gram positive strains,belonging to 6 bacterial genus)were isolated from Trachinotus ovatus during storage.The microbial species was rich at the beginning of the storage(0 d),Shewanella sp,Pseudomonas sp,Staphylococcus sp,Bacillus sp,Lactobacillus sp and Enterobacter sp all appeared.The microbial species were decreased in the middle of storage(3 d),only Shewanella sp and Pseudomonas sp were dominant in quantity.The microbial species were further decreased at the end of storage,which only 3 strains were dominant.They were Shewanella putrefaciens(No.2)48%,Shewanella oneidensis(No.5)26.6%and Enterobacter hormaechei(No.16)19.4%.The order of spoilage capabilities was as follows:Shewanella putrefaciens>Shewanella oneidensis>Enterobacter hormaechei.The spoilage ability of Shewanella putrefaciens is much higher than that of two species.Based on the results of the proportion and the spoilage capacity at the end of the storage,it was determined that Shewanella putrefaciens was the dominant Spoilage Bacteria in Trachinotus ovatus during 4℃storage.