(a) For the purpose of enforcing this chapter and determining whether or not an operation may be subject to these provisions, the Secretary upon presenting appropriate credentials is authorized to engage in one or more of the following actions:
(1) to enter any premises during normal business hours where commercial feeds, feed supplements, or dosage form animal health products are manufactured, processed, packed, or held for distribution and to stop and enter any vehicle being used to transport or hold feeds;
(2) to inspect factories, warehouses, establishments, vehicles, equipment, finished and unfinished materials, containers, and labeling; or
(3) to sample commercial feed, feed ingredients, feed supplements, or dosage form animal health products.
(b) Sampling and analysis shall be conducted in accordance with methods published by the Association of Official Analytical Chemists or in accordance with other generally recognized methods. The results of all analyses of official samples shall be forwarded by the Secretary to the correspondent named in the registration form and to the purchaser. When the inspection and analysis of an official sample indicates that a commercial feed, feed supplement, or dosage form animal health product has been adulterated or misbranded and upon request within 30 days following receipt of the analysis, the Secretary shall furnish to the registrant a portion of the sample concerned.