英语四级

听力入门英语演讲VOA慢速英语美文听力教程英语新闻名校课程听力节目影视听力英语视频

How to Help Foods Keep Their Cool

andyg 于2007-02-25发布 l 已有人浏览
增大字体 减小字体
&raquo Download Audio(mp3) By Steve Ember 2007-2-25 This is the VOA Special English Development Report.

» download audio(mp3)
by steve ember
2007-2-25

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 practical 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.

 1 2 3 下一页

分享到

添加到收藏

VOA慢速排行