Except as otherwise provided in this division, it is unlawful for any person to manufacture or sell any milk, cream, skim milk, buttermilk, condensed or evaporated milk, powdered milk, condensed skim milk, or any of the fluid derivatives of any of them or any ice cream, ice milk, cheese, or any other milk product to which has been added any fat or oil, except milk fat, or the fat naturally contained in chocolate and not separated from it, either under the name of such products, articles, or the derivatives of them, or under any fictitious or trade name. The addition, however, to the products which are commonly known as condensed skim milk, condensed buttermilk, or semisolid buttermilk of not more than 5 percent of pure cod liver oil is not a violation of this section, if the product is sold for poultry or stock feed.