110 RADIATION STANDARDS, INCLUDING FALLOUT country at all seasons permits a continuous surveillance program showing beth geographic and time variations. I did wish to point out that the use of milk as an indicater was not necessarily a matter of convenience. I think there are very important other reasons whyit is used as anindicator. . The Public Health Service, in 1957, established a raw milk sampling network composedoffive milksheds. This network was expanded to 12 stations by 1958. The experience gained here led to the establishing, in 1960, of a pasteurized milk sampling program by the Division of Radiological Health and the Division of Environmental Engineering and Food Protection. This network is now composed of some 60 stations, set up to measure the radioactivity content of milk consumed by approximately 60 million Americans. The samples are weighted with respect to the contribution of the major processing plants to the total supply and represent 90 percent. or more of the milk marketed in the area sampled. Samples are collected by State and local milk sanitation authorities and are analyzed quantitatively at the Division of Radiological Health’s regional jaboratories at Winchester, Mass.; Montgomery, Ala., and Las Vegas, ev. The analyses are for those nuclides of largest potential health importance, including iodine 131, cesium 137, barium 140, strontium 89, and strontium 90. Senator Aiken. Whenthe samples of milk are taken, they are taken of pasteurized milk. How is that pasteurized? Do they take samples of irradiated milk or the milk as it comes from the farm pasteurized by heat or what form of pasteurization is used? Dr. Cuapwick. Whatever system is used—in other words, the milk sample is taken after the milk has been pasteurized—and whatever process is used in the dairy plant is the one. Senator Arxen. Would there be any difference in the analysis of milk which has been pasteurized by heat and irradiated milk—I don’t know what ray they use—they pass it under these rays and charge 3 cents a quart more. Is there any difference in the radioactivity of milk which has been pasteurized simply by heat and milk which has been irradiated ? Dr. Cuapwicx. To the best of my knowledge, the difference in these two processes would not makeany difference in the radioactivity content. Senator ArkeNn. In irradiated milk you do not thereby enhance the radioactivity of the product ? Dr. Cuapwick. No,sir. Senator AIKEN. That is what I wanted to know. Representative Hosmer. Is there any essential difference between pasteurized and nonpasteurized milk in relation to radioactive con- tent? Dr. Cuapwick. There are some small differences between the two. Some of these differences can be accounted for simply on the basis of time. For instance, in the case of iodine there 1s decay because of the 8-day half-life, and anything that extends the time before consumption obviously reduces the iodine content. iaabemnbnenrecessansaeTORREBHOaabieette