Tennessee Code Title 53. Food, Drugs and Cosmetics § 53-11-410

(a) It is not necessary for the state to negate any exemption or exception in part 3 of this chapter and this part, or title 39, chapter 17, part 4, in any complaint, information, indictment or other pleading or in any trial, hearing or other proceeding under part 3 of this chapter and this part, or title 39, chapter 17, part 4. The burden of proof of any exemption or exception is upon the person claiming it.

(b) In the absence of proof that a person is the duly authorized holder of an appropriate registration or order form issued under part 3 of this chapter and this part, or title 39, chapter 17, part 4, the person is presumed not to be the holder of the registration or form. The burden of proof is upon the person to rebut the presumption.

(c) No liability is imposed by part 3 of this chapter and this part, or title 39, chapter 17, part 4, upon any authorized state, county or municipal officer, engaged in the lawful performance of the officer's duties.