In carrying out the provisions of this act, the department, or its employes or agents designated for the purpose, may require the attendance before it, or any of them, of any person from whom reports have been requested, or of any employe of such person, may administer oaths to and take testimony of any such person or his employe, and may require the production by such persons or their employes of any books, records, and other documentary evidence relating to the farm product about which reports have been requested.
3 P.S. § 29