The provisions of this part do not apply:

(a) To specimens of product sent to or by the Department of Agriculture or divisions thereof in Washington, DC, or elsewhere, for laboratory examination, exhibition purposes, or other official use;

(b) To material released for educational, research, and other nonfood purposes, as prescribed in § 540.2 of this subchapter;

(c) To tissues for use in preparing pharmaceutical, organotherapeutic, or technical products and not used for human food, as described in § 540.2 of this subchapter;

(d) To material or specimens of product for laboratory examination, research, or other nonhuman food purposes, when authorized by the Administrator, and under conditions prescribed by him in specific cases; and

(e) To articles that are naturally inedible by humans.