Canning Food

1、Canning Food1. Food which is kept too decays(衰退，腐败) because it is attacked by yeasts（酵母）, moulds （霉菌）and bacteria（细菌）. （食物如果存放过久，就会腐烂，因为它会收到酵母、霉菌、细菌的侵害）The canning process（罐头制造法）, however, seals the product in a container so that no infection can reach it, and then it is sterilized（灭菌、消毒） by heat. （

2、但是，罐头制造法会将食品密封在一个容器中所以一些传染源就不能接触到食物，然后它会经过高温消毒）Heat sterilization destroys all infections present in food inside the can.（高温消毒杀死了罐头里的所有的传染源）No chemical preservatives（防腐剂） are necessary, and properly canned food does not deteriorate（变坏，使恶化，衰败） during storage.（适当时罐头食品不需要化学防腐剂，也不会再储存的时候变质） The principl

3、e was discovered in 1809 by a Frenchman called Nicolas Appert（这个法则是一个叫nicalas appert 的法国人在1809年的时候发现的）. He corked（用软木塞封住） food lightly in wide-necked（广口瓶） glass bottles and immersed（沉浸、陷入） them in a bath of hot water to drive out the air, then he hammered（捶打） the corks down to seal the jars（广口瓶） her

4、metically（紧密地，密闭的）（他轻轻地用软木塞封住食品在广口瓶中玻璃瓶中，然后把它们浸没在热水浴中驱逐瓶内的空气，接着就用力地捶打软木塞使广口瓶紧密）.Apperts discovery was rewarded by the French government because better preserved food supplies were needed for Napoleon troops on distant campaigns（appert的发现被发过政府授奖，因为在长途作战中拿破仑的军队需要这些罐头食品）. By 1814 an English manufacture

5、r had replaced Apperts glass jars with metal containers and was supplying tinned vegetable soup and meat to the British navy（到1814年，一个英国的制造商将appert的玻璃广口瓶换成了金属容器，并提供镀锡罐的汤和肉给英国的海军）. The next scientific improvement, in 1860,was the result of Louis Pasteurs work on sterilization through the application

6、of scientifically controlled heat（接下来的科学改进,是在1860年,路易巴斯德工作的结果是通过科学控制热量的应用来灭菌）.2. Today vegetables,fish,fruit,meat and beer are canned in enormous quantities（现如今，蔬菜、鱼、水果、肉和啤酒大量用罐头包装）.Within three generations the eating habits of millions have been revolutionized（在漫长的时间里，数百万人的饮食习惯已经彻底改变了）.Foods that w

7、ere previously seasonal may now be eaten at any time, and strange foods are available far from the countries where they are grown（那些曾经是季节性的食物现在也可以在任何时候吃到，一些奇怪的食物在离它们生长很远的农村也可以吃到）.(2)The profitable crops many farmers now produce often depend on the proximity（接近，邻近） of a canning factory（农民们种植的有利可图的农作物

8、通常依靠于近处的罐头厂）.(3)The first stage in the canning process is the preparation of the raw food（罐头制造法的第一步就是准备生鲜食物）. Diseased（不健全的，患病的） and waste portions（部分） are thrown away; meat and fish are cleaned and trimmed（平衡的，切边，修整过的）; fruit and vegetables washed and graded（按大小分等级） for size（患病的和废弃的部分要扔掉；肉和鱼要清理和切块；

9、水果和蔬菜要清洗和根据尺寸分等级）. The jobs are principally（主要的，大部分） done by machine（这些工作主要是由机器来完成的）.The next stage, for vegetables only, is blanching（预煮，漂洗，漂白）（接下来的步骤，对于蔬菜来讲就是预煮）. This is immersion in very hot or boiling water for a short time to remove air and soften the vegetable（就是浸泡在很热的或者煮沸的水中一段时间来去除氧气和软化蔬菜）.T

10、his makes it easier to pack into cans for sterilization（这个使蔬菜更方便地装入罐头中消毒）. Some packing machines fill up to 400 cans a minute（一些包装机器一分钟能灌装400个罐头）. Fruit,fish and meat are packed raw and cold into cans, and then all the air is removed（水果、鱼和肉在生冷的时候装入罐头，然后所有的空气都被抽调）. When the cans are sealed, the press

11、ure inside each can is only about half the pressure of the outside air（当这些罐头密封了，罐头里的压力只有外界压力的一半）. This is vacuum packing（这就是真空包装）.3. During the sterilization process which follows, the cans subjected to steam or boiling water,with the temperature and duration varying according to the type of food（在灭

12、菌过程中遵循, 根据不同类型的食物，罐受蒸汽或沸水,温度和时间也不同）.(4)Cans of fruit,for example,take only 5-10 minutes in boiling water,while meat and fish are cooked at higher temperatures for longer periods（举例来说，罐头水果只要在沸水中放510分钟，但是肉和鱼要在更高温度中煮很长的时间）. After sterilization, the cans are cooled quickly to 32°C to prevent the co

13、ntents from becoming too soft（消毒之后，罐头就迅速冷却到32°C防止内装物变得太软）.The final stage before despatch（派遣、发送） to the wholesale or retail grocer is labelling, and packing the tins into boxes（在发货到批发商或零售杂货商之前的最后阶段就是贴标签和包装罐头入盒）. Nowadays,however, labelling is often printed on in advance by the canmaker and no p

14、aper labels are then required（如今，然而，标签经常是罐头制造商提前印刷好的，之后纸标签就不需要了）.Pasteurization（巴斯德灭菌法）4. The value of heat for the preservation of food has been known for thousands of years, but it was not realized until the nineteenth century that a very mild heat treatment far below the boiling point, made liqui

15、d foods such as milk keep much longer（人们对加热保存食品的价值已经知道了数千年,但直到19世纪, 才意识到一个非常温和的热处理远低于沸点,使液体食物如牛奶保持更长时间）.(5)The discovery followed the work of the French scientist Louis Pasteur on wine and beer（这种发现是在德国科学家Louis Pasteur对红酒和啤酒的工作之后）.The process, called after him pasteurization, is a carefully controll

16、ed mild heat treatment（这一过程, 是以他命名的“巴氏消毒法”,是精心控制的温和的热处理方法）. It was found that the process served two purposes; it prevented the souring of milk, and it destroyed the dangerous disease germs which sometimes occur in this product（据发现，这个过程服务于两个目的，它防止了牛奶的变酸、变质，也破坏了有时在产品中会出现的菌）.These germs include the ba

17、cteria which cause tuberculosis, undulant fever, typhoid and paratyphoid fever, dysentery, diphtheria, scarlet fever and septic sore throat（这些菌包括会导致肺结核、波状热、伤寒、副伤寒热等的细菌）.5. It has long been known to bacteria experts that the tubercle bacillus（结核杆菌） is the germ in milk which most strongly resists heat

18、 treatment（细菌专家早就知道结核杆菌是牛奶中最抵抗热处理的菌）.To destroy this organism it is necessary to heat milk to about 60°C for 15 minutes, and its destruction has always been taken as a way of testing the efficiency of pasteurization.(摧毁这种生物需要用大约60°C的温度热牛奶15分钟, 它的破坏一直是被看成是巴氏灭菌效率的一种测试) A heat treatment of th

19、is kind destroys about 99% of the common bacteria in milk, including nearly all those which cause milk to turn sour（这种热处理破坏了牛奶中99%左右的常见细菌, 其中包括几乎所有那些使牛奶变酸的细菌。）. To ensure the certain destruction of tuberculosis and other disease germs in milk, it must be held at a fixed temperature for a fixed time（

20、以确保结核病的和其他在牛奶中的细菌被破坏, 它必须在一个固定的温度放置一段固定的时间）. In Britain,for example,these conditions were defined（明确） by law in 1923 as 63-66°C for 30 minutes.This became known as the holder process,since the raw milk had to be pumped into a large tank,heated to just over 63°C,held in the tank for half an

21、 hour and then pumped out and cooled.This was a slow process and required a very cumbersome plant,so scientists worked for many years to produce a simpler,more convenient method,with less bulky equipment.6. The latest method,officially approved in Britain in 1949,is known as the high-temperature-short-time,or H.T.S.T.method.It has now almost entirely replaced the holder process.In the H.T.S.T. system,the milk flows continuously through many sections thin stainless steel pipes.During the process,the milk is held at