Food which is kept too long decays because it is attacked by yeasts (酵母菌), m

游客2023-07-27  29

问题     Food which is kept too long decays because it is attacked by yeasts (酵母菌), moulds (霉) and bacteria (细菌). The canning process, however, seals the product in a container so that no infection can reach it, and then it is sterilized (消毒) by heat. Heat sterilization destroys all infectious present in food inside the can. No chemical preservatives are necessary, and properly canned food does not deteriorate during storage.
    Today vegetables, fish, fruit, meat and beer are canned in enormous quantifies. Foods that were previously seasonal may now be eaten at any time, and strange foods are available far from the countries where they are grown. The profitable crops many farmers now produce often depend on the proximity (邻近) of a canning factory.
    The first stage in the canning process is the preparation of the raw food. Diseased and waste portions  are thrown away; meat and fish are cleaned and trimmed; fruit and vegetables washed and graded for size. The jobs are principally done by machine
    The next stage, for vegetables only, is blanching. This is immersion (浸洗) in very hot or boiling  water for a short time to remove air and soften the vegetable. This makes it easier to pack into cans for sterilization. Some packing machines fill up to 400 cans a minute. Fruit, fish and meat are packed mw and cold into cans, and then all the air is removed. When the cans are sealed, the pressure inside each can is only about half the pressure of the outside air. This is "vacuum" packing.
    During the sterilization process which follows, the cans are subjected to steam or boiling water, with the temperature and duration varying according to the type of food. Cans of fruit, for example, take only 5-10 minutes in boiling water, while meat and fish are cooked at higher temperature for longer periods. After sterilization, the cans are cooled quickly to 32℃, to prevent the contents from becoming too soft.
    The final stage before dispatch to the wholesale or retail grocer is labeling, and packing the tins into boxes. Nowadays, however, labeling is often printed on in advance by the can maker and no paper  labels are then required. [br] All of the following are the steps of canning food except ______.

选项 A、cleaning and trimming raw food
B、sterilizing canned food
C、blanching vegetables that are to be calmed
D、printing labels and packing the tins into boxes

答案 D

解析 本题需要我们阅读全文后才能做出判断。文中描述食品装罐的步骤包括:(1)准备生的食物;(2)漂洗蔬菜;(3)真空包装;(4)消毒;(5)冷却;(6)贴标签,发派给批发商或零售商。由于现代罐头制造商已提前在罐子上印刷了标签,所以加标签的步骤是在装罐过程开始以前完成的。所以我们可以判断出哪一项是整个过程中不包括的步骤。很明显应选D项。
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