Final answer:
Food irradiation involves exposing food to large doses of y rays, x-rays, or electrons to kill microorganisms and extend shelf life. Cobalt-60 and cesium-137 are commonly used in the process. The food does not become radioactive and there is no risk of exposure to radioactive material.
Step-by-step explanation:
Food irradiation exposes food to large doses of y rays, x-rays, or electrons. These photons and electrons induce no nuclear reactions and thus create no residual radioactivity. The most common method of irradiation is to expose food to cobalt-60 or cesium-137 by passing it through a radiation chamber on a conveyor belt. The food does not directly contact the radioactive material and does not become radioactive itself. Thus, there is no risk for exposure to radioactive material through eating gamma-irradiated foods.