Cal. Penal Code § 383a

Any person, firm, or corporation, who sells or offers for sale, or has in his or its possession for sale, any butter manufactured by boiling, melting, deodorizing, or renovating, which is the product of stale, rancid, or decomposed butter, or by any other process whereby stale, rancid, or decomposed butter is manufactured to resemble or appear like creamery or dairy butter, unless the same is plainly stenciled or branded upon each and every package, barrel, firkin, tub, pail, square, or roll, in letters not less than one half inch in length, “process butter,” or “renovated butter,” in such a manner as to advise the purchaser of the real character of such “process” or “renovated” butter, is guilty of a misdemeanor.