California Code, Food and Agricultural Code (Formerly Agricultural Code) - FAC § 33766

The inside surfaces of any equipment, apparatus, or container, which comes in contact with milk or its products, shall be smooth and readily cleanable and free of open seams, cracks, or crevices. All openings in covers of tanks, vats, separators or other equipment shall be protected by raised edges or otherwise to prevent the entrance of surface drainage. Every tank in which milk or a milk product is stored shall be equipped with an accurate thermometer. All surface coolers shall be equipped with condensate deflectors and tight-fitting shields.