Yogurt is a dairy product which, through fermentation. The sour look and semi-solid liquid. Which originated in the Caucasus Mountains of Russia. The yogurt contains two major types of bacteria.Streptococcus thermophilus and Lactobacillus bulgaricus, which these bacteria are reacting to a change in milk Yoghurt. Also present is a bacteria Lactobacillus casei in yoghurt to increase the nutritional value of food.