Mont. Code Ann. § 81-22-410

It shall be unlawful for any person to manufacture, mix, compound with, or add to milk, cream, or any manufactured dairy products or to transport into Montana any manufactured dairy product containing foreign animal fats or foreign animal or vegetable oils or products containing nonapproved ingredients with the intent to sell the same as milk, cream, or manufactured dairy products except as allowed under the law and/or regulations of Montana, nor shall any person possess, solicit orders for display, or sell any such article, substance, or compound as or for milk, cream, or manufactured dairy products.