Lactose is an energy source for culture bacteria. Bile tolerance is an important probiotic property. Our aim was to elucidate the effect of lactose on bile tolerance of yogurt starter culture Lactobacillus bulgaricus LB-12 and Streptococcus thermophilus ST-M5. Bile tolerance of pure cultures was determined using 0.3% oxgall in MRS THIO broth (Difco, Becton Dickinson, Sparks, MD) for L. bulgaricus and 0.3% oxgall in M17 broth (Oxoid, Basingstoke, UK) for Strep. thermophilus. Lactose was added to both broths at 0 (control), 1, 3, and 5% (wt/vol) broth. Dilutions were plated hourly for 12 h. Experiments were replicated 3 times. At 2, 4, and 12 h of incubation, lactose incorporated at all amounts, 1, 3, and 5% (wt/vol), showed higher counts of Strep. thermophilus ST-M5 in comparison to control. Lactose use at 5% (wt/vol) significantly enhanced bile tolerance of both L. bulgaricus and Strep. thermophilus compared with control.

乳糖是培养细菌的能源。胆汁耐受性是重要的益生菌性质。我们的目的是阐明乳糖对酸奶发酵剂保加利亚乳杆菌LB-12和嗜热链球菌ST-M5的胆汁耐受性的影响。对于保加利亚乳杆菌，使用MRS THIO肉汤中的0.3％oxgall（Difco，Becton Dickinson，Sparks，MD）对保加利亚乳杆菌和M17肉汤中的0.3％oxgall（Oxoid，Basingstoke，英国）对链球菌测定纯培养物的胆汁耐受性。嗜热菌。将乳糖以0（对照），1、3和5％（wt / vol）的肉汤添加到两个肉汤中。每小时将稀释液铺板12小时。实验重复3次。在孵育的2、4和12 h时，掺入量分别为1、3和5％（wt / vol）的乳糖显示出较高的链球菌计数。嗜热菌ST-M5与对照相比。5％（重量/体积）的乳糖使用显着增强了保加利亚乳杆菌和链球菌的胆汁耐受性。嗜热性与对照相比。