lactic casein

例句：

1. 1. The bacteria that producelactic acid are commonly found in fermented foods.
   产生乳酸的细菌通常存在于发酵食品中。
2. 2. Lactic acid isa common ingredient in many types of cheeseand yogurt.
   乳酸是许多类型奶酪和酸奶的常见成分。
3. 3. In the human body, lactic acid is produced during exerciseand helps to recharge the muscles.
   在人体中，乳酸是在运动时产生的，有助于为肌肉充电。