Suitable means or appliances shall be provided for the proper cleaning or sterilizing of freezers, vats, mixing cans or tanks, conveyors, and all utensils, tools and implements used in making or handling cream, ice cream, butter or cheese and all such apparatus shall be thoroughly cleaned as promptly after use as practicable. (1921, c. 169, s. 2; C.S., s. 7251(b).)