沈阳市部分市售酸奶乳酸菌的分离鉴定

Isolation and Identifaction of Lactic Acid Bacteria in Yogurt Sold In Shenyang City

目的：探讨沈阳市部分市售酸奶和益生菌饮品的活菌数量和种类与国家规定标准的符合情况.方法：利用倍比稀释法分离酸奶和益生菌饮品中的乳酸菌并进行活菌计数,对分离得到的菌株进行革兰染色及生化反应鉴定.结果：本次调查的4个厂家的11种产品活菌计数范围为1.6 ×104 ～3×108 cfu/ml （g）,乳酸菌含量符合国家规定标准的占81.8％.分离的38个菌株包含革兰阳性杆菌26株,革兰阳性球菌12株.标识菌名与实际相符的达到72.7％,标明含有益生菌的6个样品与标识的菌名相符的仅有3种,标明含有双歧杆菌的样品本次实验未检出双歧杆菌.结论：本次调查的普通酸奶和益生菌饮品的活菌计数和种类基本符合国家规定标准.但是部分市售酸奶和益生菌饮品所添加的菌种和活菌计数与产品包装上标识不符.

Objective： To investigate the number and types of live bacteria in yogurt and probiotic drink and the compliance with the national standard of complains. Methods： Coubling dilution was used to separate lactic acid bacteria in yogurt and probiotic drink and viable count was done, and the isolated strains were identified with Gram staining and biochemical reaction. Results： The range countingof live bacteria was 1.6 × 104 to 3 ×108 cfu/ml （g） in 11 products from 4 factory. Lactic acid bacteria content was 81.8% in compliance with national standards. The 38 strains of gram positive bacilli contained 26 strains of gram positive bacilli and 12 strains of gram positive cocci. Identification of bacteria named corresponded to the actual for 72. 7%. And 6 samples marked probiot- ic conformed to only 3. Samples labeled as containing bifidobaeterium in this experiment had no detection of bifidobacterium. Conclu- sion： The number and types of live bacteria in yogurt and probiotic drink are basically in line with national standards. But the type and count of live bacteria in some yogurt and probiotic drink does not match the identification of product packaging.