Public health scientists have had an interest in food irradiation for a hundred years and more. The first investigations occurred within a few years of the discovery of x-ray and short wavelength by the German physicist Roentgen, in 1895. German and French scientists carried on studies on pasteurization of food by radiation until 1914 and the war years. The problem was an unacceptable taste following irradiation. In 1921, the x-ray was reported by the scientists of the United States Department of Agriculture (USDA) to be effective in killing Trichinella cysts in pork and that it could kill disease-causing organisms and halt food spoilage.