A person may not be prosecuted under chapter 401, and sections 482 to 488‑A, 490 and 640 to 643, when that person can establish proof of purchase, and a guaranty signed by the person residing in the United States from whom the purchase was made, to the effect that the article in question is not adulterated or misbranded within the meaning of this chapter or chapter 103.   [PL 2005, c. 512, §24 (AMD).]