Cal. Food & Agr. Code § 5721
If the director by regulation designates any plant, appliance, or other thing as liable to be infected or infested with any pest, and provides for notifying the commissioner of its arrival as required by Article 1 (commencing with Section 6501), Chapter 3, Part 2 of this division, he may include in the regulations standards of cleanliness for the plant, appliance, or other thing and provide for the certification by the commissioner of the county of origin of shipment that it conforms to the standards of cleanliness. The regulations may provide for the qualification of certain counties or certain areas where in the opinion of the director the standards of cleanliness are maintained in respect to all shipments of the designated plant, appliance, or thing. The regulations may also provide for shipments which originate in areas that are so qualified.
Ca. Food and Agric. Code § 5721