The invention can be used in varies industries, in particular, in the food, paper, chemical and pharmaceutical industries. The inventive method consists in separating unpasteurised cow milk in a separator, wherein a skimmed milk and fats are separated. Said method is characterized in that it consists in pasteurising said skimmed milk in a pasteuriser at a determined temperature, in cooling said milk and conveying it to an intermediate balance tank from which the milk is supplied to a micro-filtering membrane-type filter for dividing it into casein and whey proteins, in supplying the separated casein protein to a membrane-type ultrafiltration-defiltration filter, wherein the concentrated product is transferred to a drier for drying, and in cooling and packing the thus produced water-soluble casein flour.
