California Code
ARTICLE 1 - Milk Fat or Butter Fat
Section 38152.

38152. Milk fat or butterfat is the fat of milk. It shall have a Reichert-Meissl number not less than 24 and a specific gravity not less than 905/1000. In determining the specific gravity, milk fat at 40 degrees centigrade shall be compared with water at 40 degrees centigrade.

(Amended by Stats. 1967, Ch. 9.)