Many Americans harbor a grossly distorted and exaggerated view of most of the risks surrounding food. Fergus Clydesdale, head of the department of food science and nutrition at the University of Massachusetts-Amherst, says bluntly that if the dangers from bacterially contaminated chicken were as great as some people believe, the streets would be littered with people lying here and there.
Though the public increasingly demands no-risk food, there is no such thing. Bruce Ames, chairman of the biochemistry department at the University of California, Berkeley, points out that up to 10% of a plant s weight is made up of natural pesticide (杀虫剂). Says he, Since plants do not have jaws or teeth to protect themselves, they employ chemical warfare. And many naturally produced chemicals, though occurring in tiny amounts, prove in laboratory tests to be strong carcinogens a substance that can cause cancer. Mushrooms (蘑菇) might be banned if they were judged by the same standards that apply to food additives (添加剂). Declares Christina Stark, a nutritionist at Cornell University: We ve got far worse natural chemicals in the food supply than anything man-made.
Yet the issues are not that simple. While Americans have no reason to be terrified to sit down at the dinner table, they have every reason to demand significant improvements in food and water safety. They unconsciously and unwillingly take in too much of too many dangerous chemicals. If food already contains natural carcinogens, it does not make much sense to add dozens of new man-made ones. Though most people will withstand the small amounts of contaminants generally found in food and water, at least a few individuals will probably get cancer one day because of what they eat and drink.
To make good food and water supplies even better, the Government needs to tighten its regulatory standards, stiffen its inspection program and strengthen its enforcement policies. The food industry should modify some long-accepted practices or turn to less hazardous alternatives. Perhaps most important, consumers will have to do a better job of learning how to select and cook food properly. The problems that need to be tackled exist all along the food-supply chain, from fields to processing plants to kitchens.

A. plants absorb useful chemicals to promote their growth
B. plants produce certain chemicals to combat pests and diseases
C. farmers use chemicals to protect plants against pests and diseases
D. farmers use man-made chemicals to dissolve the natural chemicals in plants