Cal. Food & Agric. Code § 66644

Any proceeding by the commission to enforce this chapter or by a handler applying for relief from rules, orders, or regulations of the commission may be commenced either in the county in which the defendant or any of the defendants reside or in which any act or omission or part thereof complained of occurred, or in the county of the principal office of the commission. The commission may be sued only in the county of its principal office.