The Secretary of Agriculture, or such officer or employee of the Department of Agriculture as may be designated by him, upon written application of any cooperative association, incorporated or otherwise, which is in good faith owned or controlled by producers or organizations thereof, of milk or its products, and which is bona fide engaged in collective processing or preparing for market or handling or marketing (in the current of interstate or foreign commerce, as defined by section 610(j) of this title), milk or its products, may mediate and, with the consent of all parties, shall arbitrate if the Secretary has reason to believe that the declared policy of the Agricultural Adjustment Act [7 U.S.C. 601 et seq.], as amended, would be effectuated thereby, bona fide disputes, between such associations and the purchasers or handlers or processors or distributors of milk or its products, as to terms and conditions of the sale of milk or its products. The power to arbitrate under this section shall apply only to such subjects of the term or condition in dispute as could be regulated under the provisions of the Agricultural Adjustment Act, as amended, relating to orders for milk and its products.