冷冻鲣鱼中产组胺菌的分离筛选及其生物学特性研究

Study on Isolation and Biological Characteristics of Histamine-forming Bacteria in Frozen Storage of Raw Skipjack Tuna

采用Actis’s鉴别培养基,初步筛选鲣鱼组织中的产组胺菌;结合高效液相色谱法分析初步分离菌株的产组胺能力。研究温度和pH因素对产组胺菌生长以及组胺产生的影响。通过生理生化、形态和16S rDNA基因序列分析鉴定产组胺菌。试验结果表明,分离得到两株产组胺菌,分别记为J2和J4。这两株菌在添加L-组氨酸的胰酶大豆肉汤里均能够产生组胺。菌株J2和J4最适生长温度均为30℃,最适pH分别为7和6。菌株J2和J4产组胺的最适温度分别为25℃和30℃,最适pH均为5,在适宜的实验条件下组胺产生量最大值为12.47mg/L。根据菌株的形态、生理生化、生长和产组胺特性以及16S rDNA基因序列分析,J2和J4均与蜡状芽孢杆菌(Bacillus cereus)的亲缘关系最近。

Histamine-forming bacteria were selected from the prescreening step using Actis’s identification medium from skipjack tuna tissue,and true histamine formers were confirmed by HPLC method.Effects of temperature and pH on growth and histamine production of histamine-forming bacteria were studied.They were further identified by physiology,biochemistry indicators,morphology and 16 S rDNA gene sequence analysis.The results showed that two histamine formers isolated from skipjack tuna tissue were named as J2 and J4,which could produce histamine in trypticase soy broth supplemented with 1.0% L-histidine.The optimal temperature of growth of them were both 30 ℃,and the optimal growth pH were 7 and 6,respectively.The optimal temperature of histamine production of them were 25 ℃ and 30 ℃,respectively.The optimal pH was both 5.The maximum of histamine reached 12.47 mg/L under the suitable culture condition.The strains J2 and J4 had the closest relationship with Bacillus cereus,based on theirs,morphology,physiochemical properties,characteristic of growth and histamine production and 16 S rDNA sequence analysis.