A carrier which is subject to the jurisdiction of the Public Utilities Commission that transports any fruits, nuts, or vegetables in the ordinary course of its business as a carrier shall not be deemed to be in violation of any provision of this division, unless such carrier shall willfully fail or refuse to stop the transportation of any fruits, nuts, or vegetables with reasonable dispatch after being notified in writing by any enforcing officer of this division that such products are found to be delivered for shipment in violation of this division.