Sweet butter that is used in ice cream, frozen dairy dessert, and frozen dessert shall be unsalted butter made from sweet cream that is free from undesirable flavor or odors. It shall have a rating of not less than 92 in accordance with the standards for quality of creamery butter that are established in Article 2 (commencing with Section 37131) of Chapter 3. Cream to which has been added ripener or starter, or cream that has been neutralized, is not sweet cream within the meaning of this section.