Milk is exposed to secondary contamination during milking (total bacteria count, coliform bacteria, etc.). Main sources of contamination are dirty surfaces of the mammary gland and its surrounding, hands and clothes of milkers, environment, stable or parlor, milking equipment, water and other manipulation of milk. One of the most important sources of contamination of milk are milking machines. Slightest remnants of milk are very good substrate for microorganisms, which significantly impair the final quality of milk in compliance with the procedure and principles of cleaning and disinfection of milking equipment.