Mich. Comp. Laws § 289.7133

Sec. 7133. (1) All products manufactured under terms of this chapter may be sold in colored artificial casings or containers only if the products are in complete compliance with all applicable regulations of the United States department of agriculture. These products shall not be sold in colored natural casings. (2) In addition to the requirements of section 1105(1)(a), any product manufactured under the terms of this chapter is adulterated if it is the product of an animal which has died otherwise than by slaughter.