2. Food irradiation technology was patented in 1905 and developed in the 20th century. Based on radiation processing technology, food is treated with high-energy rays generated by ionizing radiation such as X-ray, γ-ray or high-speed electron beam, so as to achieve the purposes of killing insects, sterilizing, inhibiting physiological processes, improving food hygiene quality, maintaining nutritional quality and flavor, and prolonging shelf life. Radiation can also kill insects and their eggs and larvae in food. After more than 40 years of research, about 50 kinds of irradiated foods in about 36 countries have been recognized. As the World Health Organization has concluded, irradiated food is as safe and healthy as pasteurized food.