在美国,良好的运翰和先进的保鲜防腐方法,使人们一年四季均可选择各种各样的食品。这有利也有弊。虽然新鲜的水果和蔬菜随时可以买到,但许多食品经过过度加工,已经失去了许多基本的营养价值。有些化学品,像用于某些肉类食品防腐的亚硝酸盐,已被认为能引起癌症。无孔不入的电视广告,怂 In the United States, good transporters and advanced antiseptic and preservative methods enable people to choose all kinds of foods throughout the year. This has both advantages and disadvantages. Although fresh fruits and vegetables can be purchased at any time, many food products have lost many of their basic nutritional value through over-processing. Some chemicals, like nitrite used for the preservation of certain meat products, have been considered to cause cancer. Pervasive TV commercials,