理工类相同项单选集试卷（理工类）_0.docVIP

试卷第 PAGE 1 页共 NUMPAGES 1 页 理工类相同项单选集试卷（理工类） 姓名:_____________ 年级:____________ 学号:______________ 题型 选择题 填空题 解答题 判断题 计算题 附加题 总分 得分 评卷人 得分 1、Irradiating Food Irradiating fruits, vegetables, pork and chicken to kill insects and bacteria has been approved by the Food and Drug Administration over the past decade or so. Irradiation of other meats, such as beef and lamb, is being reviewed. Federal approval does not require that industry adopt the process, and few food processors presently offer irradiated products. Market studies have shown that many consumers are afraid that eating irradiated foods may cause cancer, despite scientific studies that prove the safety of treated foods. Some people argue that more severe government inspection, higher food-safety standards, and more careful-preparation practices by consumers are all that is needed to ensure that food is safe. Consequently, companies currently see no need to spend millions of dollars outfitting processing plants with the equipment necessary for a process that very few shoppers are in favor of. All supermarkets that sell irradiated food must label the food either directly on the packaging, or, in the case of bulk items like fruits and vegetables, by placing a sign nearby. There is no requirement for the labeling of irradiated food served by chain restaurants or hospitals that buy directly from distributors, nor any regulations for products that contain irradiated ingredients. Presently, the FDA allows food to be treated with three types of radiation—gamma rays, high-energy electrons, and X rays—and sets limits on doses, depending on the type of food. The principle is that the dose to be used for a certain type of food should not exceed the amount that is sufficient to kill most harmful insects and bacteria present in it. Different types of food, because of their molecular compositions, may require different doses of radiation.According to the passage, killing insects and bacteria present in fo