No member of, or delegate to Congress, or Resident Commissioner, shall be admitted to any share or part of any contract provided for in the regulations in this subpart or to any benefit that may arise therefrom, but this provision shall not be construed to extend to such contract if made with a corporation for its general benefit, and shall not extend to any benefits that may accrue from the contract to a member of, or delegate to Congress, or a Resident Commissioner in his capacity as a farmer.