For the purposes of this chapter, producers shall mean persons who raise their own products on land owned or leased by themselves. In the sale of such products, producers may sell by agent; provided, that satisfactory evidence must be furnished by such agent as to his or her authority to act for his or her principal. Such authorization shall be for a limited period of time only, not exceeding ninety (90) days, and for reasons which must be passed upon by the city manager as good and sufficient. (Prior code § 31.01.001)