Abstract: A process for producing kefir is provided which involves normalization of purified cow milk with respect to the content of dry solids by ultrafiltration of the milk at a temperature of 50.degree.-55.degree. C. till the content of dry solids is increased in the normalized milk by 0.5-4.0% by mass, further heat treatment at the temperature of 140.degree. C., introduction into the normalized milk of a leaven prepared using kefir fungi, leavening of the resulting mixture to a pH of 5.0-4.7, residence of the leavened mixture at a temperature of 18.degree.-20.degree. C. to a pH of 4.7-4.5, followed by packing.

Abstract: A sour milk product is composed of proteins, milk and vegetable fats, lactose, dextrin maltose, saccharose, water, bifidobacteria, ferrous sulphate and vitamins, A, D.sub.2, E, C, B.sub.1, B.sub.2, B.sub.3, B.sub.6, B.sub.c and PP with the following proportion of ingredients, in mass per cent:milk fat: 2.5-2.7vegetable fat: 0.8-1.0lactose: 2.0-2.2dextrin maltose: 1.6-1.8saccharose: 3.3-3.5ferrous sulphate: 0.00325-0.00335vitamins: 0.0064-0.0066proteins: 1.6-1.8bifidobacteria (ml): 10.sup.8 -10.sup.9water: the balance.