W. Va. Code § 19-5-6: Exemption from prosecution.

No person, firm, organization or corporation shall be prosecuted under the provisions of this article:

(a) When he or it can establish by satisfactory evidence that he or it was not a party to the packing, grading or marking of such fruits or vegetables;

(b) When he or it can establish that the fruits or vegetables offered for sale have passed inspection by an authorized inspector of this state and bear the official West Virginia inspection stamp, or by an inspector of the United States Department of Agriculture and found to be packed in accordance with the requirements of the commissioner of agriculture of West Virginia.