The Commissioner shall make such investigations or inspections as he deems necessary to determine whether any person has violated, or is violating, any provision of this Article or any regulation promulgated thereunder, and when any biological residue is  found in or on any animal, animal product, or animal feed, the Commissioner may make such investigation or inspection as he deems necessary to determine the source of the substance which resulted in the biological residue. (1971, c. 1183, s. 6.)