Cal. Food & Agric. Code § 33520

Multiuse containers, equipment and utensils used in the handling, storage and transportation of milk shall be made of smooth, nonabsorbent, corrosion-resistant, nontoxic materials and shall be so constructed as to be easily cleanable. All containers, equipment, and utensils shall be in good repair. All milk pails used for handmilking and stripping shall be seamless and of the hooded type having an opening not exceeding one-third of the area of an open pail of the same size. All can lids shall cover the pouring lip so as to protect such lip from contamination.