绿茶饮料污染菌人参土芽孢杆菌的鉴定和分析

摘要

分析了某批绿茶饮料出现颜色变浅,出现少量片状沉淀的变质原因.首先采用平板计数琼脂、橙血清和乳酸菌培养基分离和计数污染菌,该菌在原料——茶叶和糖中有检出,原位清洗(Clean In Place,CIP)后能在管道中检出.16S rRNA序列分析鉴定其主要污染菌最接近脂环酸芽孢杆菌属(Alicyclobacillus)和人参土芽孢杆菌(Bacillus ginsengihumi).但是从生理生化特性来看,该污染菌生长pH范围4.68～7.30,最适pH4.68,生长温度范围为15 ～45℃,最适生长温度为40℃,不符合脂环酸芽孢杆菌属耐酸耐热特性.综合16S rRNA序列分析和生理生化特性,该菌被鉴定为人参土芽孢杆菌.成品中的污染来自原料,因萃茶和灌装管路的CIP系统未分开,而该菌能耐受原位清洗的酸洗、碱洗和热水洗,通过灌装线污染成品.人参土芽孢杆菌首次被发现是一种低酸性饮料——绿茶饮料的污染菌,该菌对CIP清洗有很好耐受性,导致成品灌装线的污染.%The reason of one batch of green-tea beverage faded with precipitation was studied.Firstly,the contaminated microorganisms of the samples were counted and isolated on PCA,OSA and MRS agars.The isolates were identified to be close to both Alicyclobacillus spp.and Bacillus ginsengihumi by 16S rRNA sequence analysis.It could grow from 15 to 45 ℃,while 37-40 ℃ was the best.And it could grow from pH 4.68 to 7.30,while pH 4.68 was the best.Those characters were greatly different from that of Alicyclobacillus-the thermo-acidophilic bacteria but very similar to that of mesophilic bacteria B.ginsengihumi.The bacteria were identified as B.ginsengihumi.The materials sugars and tea were suspected to be the pollution resources.B.ginsengihumi might contaminate filling system from extraction system through shared CIP systems while it was resistant to the cleaning of hot acid,water and lye.Bacillus ginsengihumi was firstly found to deteriorate a low acid drink-green tea beverage,with high resistance to CIP.