The things we eat can be divided into natural and man-made substances. Some people feel that only natural foods are healthy and that all man-made ingredients (原料) are to be avoided. But many natural chemicals, found in plants and animals, are harmful when eaten, and some laboratory----made substances increase the nutritional value of food.Other chemicals have natural and man-made forms that are exactly alike: vitamin C is vitamin C, whether it comes from a test tube or from an orange.Like “chemical”, “man-made” doesn’t necessarily mean “not fit to eat”.
Food additives are used for many reasons. We add sugar and salt and other things to foods we prepare at home to make them taste better. Food producers have developed a range of additives that stabilize, thicken, harden, keep dry, keep wet, keep firm, or improve the appearance of their products. Additives can make food more convenient or nutritious, give it a longer shelf life, and make it more attractive to the consumer, thus increasing the sales and profits of the producers.
Food additives are presently the centre of a storm of serious argument. Food producers have been known to use additives that have not been proved safe; some substances in common use have been proved unsafe and have been taken off the market. Many people feel there’s a risk of eating food to which anything has been added. But food additives are now regulated by the FDA of the federal government, and new additives are subjected to strict testing before they can be placed on the market. For most people, the chances of developing serious side effects from the long-term use of presently approved food additives are very slim.
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