Before the war, Australia was a great food-producing country—in fact, she had, per capita, the greatest food supply in the world—yet there was no one department in the Commonwealth government in which the task of administering that food supply was centralized. No constitutional or statutory basis existed for control by the Commonwealth of food production, processing, and distribution. Agriculture was a function of the individual states, all of whom maintained separate departments of agriculture. Since the export of certain basic agricultural products such as wool and wheat was essential to the economy of Australia, a loosely-knit system of marketing boards affiliated with the Commonwealth Department of Commerce had developed to supervise the sale of these commodities. However, several of these boards, such as the Dairy Produce Board and the Dried Fruits Export Control Board, which had derived their powers originally from special legislation, experienced difficulties because of constitutional restrictions. In 1936, the Privy Council declared invalid a series of marketing laws relating to dried fruits, dairy products, and wheat. Section 92 of the Constitution, which requires free trade among the states, was interpreted by the Council as constraining the Commonwealth as well as the states. Under the wartime emergency powers granted to the Commonwealth by the National Security Regulations of 1939–40, these agencies and many additional similar ones received legal basis.