((a)) ** Secretary’s duty to conduct; purpose of referendum** The Secretary shall conduct a referendum among producers, who during a representative period determined by the Secretary have been engaged in the production of potatoes, for the purpose of ascertaining whether the issuance of a plan is approved or favored by such producers. When the issuance of a plan would subject importers to the terms and conditions of a plan, the Secretary also shall conduct the referendum among importers, who during a representative period determined by the Secretary have been engaged in the importation of potatoes, for the purpose of ascertaining whether the issuance of such plan is approved or favored by such importers.

((b)) ** Required margin of approval** No plan issued under this chapter shall be effective unless the Secretary determines that the issuance of such plan is approved or favored by not less than a majority of the producers voting in such referendum or a majority of the producers and importers when the issuance of a plan would subject importers to the terms and conditions of a plan, voting in such referendum.

((c)) ** Amendments** The failure of potato producers and importers to approve an amendment to any plan issued under this chapter shall not be deemed to invalidate such plan.

((d)) ** Penalties for disclosure of confidential information, ballots and reports** The ballots and other information or reports which reveal or tend to reveal the vote of any producer or his production of potatoes, or any importer or the volume of potatoes imported by such importer, shall be held strictly confidential and shall not be disclosed. Any officer or employee of the Department of Agriculture violating the provisions hereof shall upon conviction be subject to the penalties provided in .section 2619(c) of this title