当你走进本地的超级市场购置物品的时候,你总会自然而然地去浏览陈列在货架上的数以百计的种种罐头食品。眼下,几乎每一种食品,如肉类、蔬菜、鱼类、水果甚至形形色色的饮料,都做成罐头在市场上出售。在选购各种罐头食品的时候,你当然认为封装在这些罐头里的食品都是新鲜可食的,尽管这些食品被封装在罐头里可能已经有好几个月了。好几百年以来,人们一直在寻求保存食品的办法,以便在冬季以及歉收的季节来食用这些食品。虽然人们早就知道腌渍及腌制是保存食品(尤其是肉类)的 As you walk into local supermarkets to buy items, you’ll naturally be able to browse hundreds of different types of canned food on display. Right now, almost every type of food, such as meat, vegetables, fish, fruits and even a wide variety of drinks, is made ready for sale on the market. When choosing a variety of canned foods, you certainly think the food packaged in these cans is fresh and edible, although it may have been months since the foods were packaged in cans. For hundreds of years, people have been looking for ways to conserve their food in order to consume it during the winter months and during the harvest season. Although it has long been known that pickled and marinated foods are preserved, especially meat