No marketing order or major amendment to it, which directly affects producers or producer marketing, that is issued pursuant to this chapter, shall be made effective by the director unless and until the director finds one or more of the following has occurred:
(a) It has been assented to in writing by not less than 65 percent of the producers that are engaged, within the area specified in the marketing order or amendment to it, in the production for market, or engaged in the producer marketing, of not less than 51 percent of the commodity which is specified in the marketing order or the amendment to the marketing order in commercial quantities.
(b) It has been assented to in writing by producers that produce not less than 65 percent of the volume of the commodity and by 51 percent of the total number of producers that are so engaged.
(c) It has been approved by producers in a referendum among producers that are directly affected. The director may make the finding if the valid votes cast in the referendum represent not less than 40 percent of the total number of producers of the commodity of record with the department, and if the producers that cast ballots in the referendum in favor of the marketing order or amendment to it represent not less than 65 percent of the total number of producers that cast ballots in the referendum and marketed not less than 51 percent of the total quantity of the commodity which was marketed in the next preceding marketing season, or the current marketing season if the harvest and delivery of the commodity to handlers is complete, by all of the producers that cast ballots in the referendum or if the producers that cast ballots in the referendum in favor of the marketing order or amendment represent not less than 51 percent of the total number of producers that cast ballots in the referendum and marketed not less than 65 percent of the total quantity of the commodity which was marketed in the next preceding marketing season, or the current marketing season if the harvest and delivery of the commodity to handlers is complete, by all of the producers who cast ballots in the referendum. The quantity of the commodity delivered by the producer may be stated on the referendum ballot returned by each producer or may be obtained by requiring handlers to report that volume pursuant to Section 58775.