“Drink cow's milk for your health” - is sung in an old children's song. But many modern nutritionists claim that milk is food for babies. But fermented milk products are excellent nutrition for everyone. Especially kefir. This is the most unusual and interesting product of all that is produced from milk. Kefir is a dietary product, a medicine, a cosmetic product, and one of the main components of many drinks. For a wide range of readers.