VOA慢速英语-Development Report - Helping Foods Keep Their Cool

How to build an evaporative cooler. Also, how to prepare fruits and vegetables for cold storage¹. Transcript² of radio broadcast:
08 June 2008

This is the VOA Special English Development Report.

Before refrigerators, homes usually had ice boxes. But another way to keep food cool without the need for electricity is to use an evaporative cooler. This is easy to make and does not even use ice.

A common design is a tall box with food placed on several shelves inside. The shelves are pieces of metal with many small holes through them. The sides of the box are covered with pieces of thick cloth.

Containers of water are placed at the top and bottom of the cooler. The ends of each piece of cloth lie in the water so the cloth stays wet.

Put the cooler in the open air but not in the sun. Air will pass through the wet cloth. The inside of the box will stay several degrees cooler than the outside air temperature. And this may be cool enough to keep foods fresh at least for a short time.

Cold storage in a freezer, however, can keep foods in good condition for months after the growing season. Yet foods can be damaged if they are kept too cold.

The British development group Practical³ Action says the best way to prepare foods for storage is at harvest time while still in the field. Use a sharp knife to avoid damage.

Place the harvested items⁴ on a clean surface or directly⁵ into storage containers. Do not put them on the ground.

Use clean water to remove dirt, and keep the water clean. Usually it is better not to remove outer leaves from fruits and vegetables before storage. Without the leaves, food can become dry.

Fruits and vegetables must be cool from field heat before they are put into storage. If they are placed in cool water, however, it can spread fungus⁶ throughout⁷ the food. A better idea is to harvest foods either early or late in the day, then leave them to cool naturally.

Some fruits and vegetables must be stored at zero to four degrees Celsius⁸. Any colder, and they might be damaged. Others need four to eight degrees. And still others must be stored above eight degrees.

Wet the fruits and vegetables so they do not become too dry. The best time to do this is before storage. Cover the items in plastic once they reach the right "critical⁹ temperature" for storage. Most fruits and vegetables need the relative humidity¹⁰ in storage to be kept between eighty-five and ninety-five percent.

Finally, leave space between the food containers and the walls of the storage area so air can flow. Keep the space clean. And try not to open the doors too often.

And that's the VOA Special English Development Report.

1 storage   

n.存储器，储藏，保管，库存，仓库

参考例句：

• How much will you have to pay the warehouse for storage?你得付多少仓库保管费？
• He is charging a storage battery.他在为蓄电池充电。

2 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

3 practical   

adj.实际的，实践的；实用的，应用的；有实际经验的

参考例句：

• He is a practical person.他是位很讲实际的人。
• Your invention is clever,but not practical.你的发明很巧，但不实用。

4 items   

n.物料项目 （任何一种自制或采购的零部件或组装件，如最终产品、部件、子部件、零件或原材料）；条( item的名词复数 )；一项；一则；一件商品（或物品）

参考例句：

• Bulky items will be collected separately. 大件物品将分开收集。
• Customers with ten items or less can use the express lane. 购买十件商品以内的顾客可使用快速购物通道。

5 directly   

adv.直接地，径直地；马上，立即

参考例句：

• I will telephone you directly I hear the news.我一听到消息，马上打电话给你。
• She answered me very directly and openly.她非常坦率地、开门见山地答复了我。

6 fungus   

n.真菌，真菌类植物

参考例句：

• Mushrooms are a type of fungus.蘑菇是一种真菌。
• This fungus can just be detected by the unaided eye.这种真菌只用肉眼就能检查出。

7 throughout   

adv.到处，自始至终；prep.遍及，贯穿

参考例句：

• These magazines are sold at bookstores throughout the country.这些杂志在全国各地书店均有发售。
• Guilin is known throughout the world for its scenery.桂林以山水著称于世。

8 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

9 critical   

adj.批评的，评论的；危急的，紧要的；临界的

参考例句：

• We are at a critical time in history.我们正处在历史的危急时刻。
• Now that the situation becomes critical,one must keep calm.事到临头，要沉住气。

10 humidity   

n.湿度，潮湿，湿气

参考例句：

• The house is not comfortable tonight ,because of the high humidity.由于湿度高，今晚屋子里不舒服。
• It's difficult to work because of the humidity.由于空气潮湿，工作很困难。