In lieu of the certification stamp required under this chapter, the director may authorize issuance of a permit to any person or firm engaged in preparing avocados for market on an intermittent basis, or any other person on an emergency basis. The permit shall have an assigned number, and the containers of avocados for which the permit is issued shall be printed or labeled with the words “avocado permit” immediately followed by the number designation. Except on an emergency basis, a permit shall not be issued for more than ten containers and not more than four permits may be issued to any person, firm, or family of the same household during the calendar year.