“Handler” means any person who engages in the operation of selling or marketing navel oranges for fresh consumption which he or she has produced, purchased, or acquired from a producer, or which he or she is marketing on behalf of a producer, whether as owner, agent, employee, or broker or otherwise. It does not, however, include a retailer, except a retailer who purchases or acquires from, or handles on behalf of, any producer navel oranges which were not previously subject to regulation by the commission.