Wis. Stat. § 97.10: Prohibited acts.

(1) The sale of any food that is adulterated or misbranded is prohibited.

(2) It is unlawful to manufacture, prepare for sale, store, or sell food unless the food is protected from filth, flies, dust or other contamination or unclean, unhealthful or insanitary conditions.

(3) No person shall be subject to the penalties of s. 97.72 for having violated sub. (1), if he or she establishes a guaranty or undertaking signed by, and containing the name and address of the person residing in this state from whom the article was received in good faith, to the effect that such article is not adulterated or misbranded within the meaning of ss. 97.02 and 97.03.