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Food irradiation, also known as ionizing radiation sterilization, is a process of exposing food to ionizing radiation. It can damage the DNA structure of organisms by electromagnetic radiation, so that the organism is unable to continue to multiply, as well as plants stop growth and differentiation to kill the microorganisms, bacteria, viruses and insects present in the food. This treatment is commonly used to preserve food, reduce the risk of food borne illness, guard against the spread of invasive pests, promote the production of fruit juice, enhance the rehydration and delay or inhibit sprouting or ripening. Currently, food irradiation is permitted by over 60 countries, with about 500,000 tons of food annually processed worldwide. The regulations about the food variety and the processing methods of food irradiation, vary greatly from country to country. In Austria, Germany and many other countries of the European Union only dried herbs, spices, and seasonings can be processed with irradiation and only at a specific dose, while in Brazil all foods are allowed at any dose. Because the radiation used by food irradiation poses a threat to human body, so a tungsten alloy shielding is usually used for shielding it.

Food irradiation has many advantages, such as a certain doses(<5kGy) of  irradiation does not make significant sensory changes on foods; even with high doses (> 10kGy), the chemical changes on foods are very small; food irradiation does not produce the non-food substances residues and can maintain the original features of foods in highest degree; food irradiation can be irradiated in the frozen state; the penetrating power of radiation is strong, uniform and fleeting, so that it can accurately control the irradiation process; there is no strict requirements on food packaging when foods are irradiated. Therefore, food irradiation is widely used in the irradiation quarantine treatment of import and export fruits and agricultural and livestock products, killing pests in the dried fruits, dehydrated vegetables and meat, irradiation sterilization of spices and research of comprehensive applications of other preservation treatment.

The rays used during the food irradiation, such as X rays, gamma rays and electronics, are harmful for human body, so a tungsten alloy shielding is usually used for shielding them when food irradiation is conducted. The shielding performance of a metallic material is closely related to its density, tungsten alloy has great shielding performance due to its high density.