California Code, Food and Agricultural Code (Formerly Agricultural Code) - FAC § 34593

Market milk or the fluid derivative of market milk which is used in the preparation of milk shakes or other mixed milk drinks shall be dispensed or poured from standard milk bottles or single service containers which have been filled and sealed or capped in a milk products plant.

This section does not prohibit the use of homogenized market milk or flavored dairy drinks drawn from a milk dispensing device that is approved pursuant to Section 34594 in the preparation of milk shakes or other mixed milk drinks.