Bacteria can make foods go bad. This is true of cooked foods as well as fresh foods. The problem is especially dangerous when the air around food is warm. High heat kills bacteria. But warm, wet conditions help bacteria grow.
細(xì)菌能使食物變壞。這對于熟食和新鮮食物都是如此。當(dāng)食物周圍的空氣很溫暖時，這個問題尤其危險。高溫殺死細(xì)菌。但溫暖潮濕的環(huán)境有助于細(xì)菌生長。
So, the best way to protect food is to keep it in a cool place. There are several ways to keep food cool without the need for electricity. Some refrigerators, for example, are powered by gasoline motors.
所以，保護(hù)食物最好的方法就是把它放在涼爽的地方。有幾種方法可以使食物保持涼爽而不需要電力。例如，一些冰箱由汽油發(fā)動機(jī)驅(qū)動。
There are less costly ways than refrigeration to keep food cool. An ice box is a simple device. It is made mostly of wood. The inside walls are covered with metal. A big piece of ice is placed in the bottom. Millions of homes had ice boxes until refrigerators became common in the nineteen forties.
有比冷藏更省錢的方法來保持食物的涼爽。冰盒是一種簡單的設(shè)備。它主要由木頭制成。里面的墻被金屬覆蓋著。一大塊冰被放置在底部。在20世紀(jì)40年代冰箱普及之前，數(shù)以百萬計的家庭都有冰盒。
An ice box will keep food from spoiling for several days if the outside temperature is not too warm. If the box is kept out of sunlight, the ice will last longer.
如果外面的溫度不太熱，一個冰盒可以防止食物腐爛幾天。如果把盒子放在陽光下，冰就會變長。
Probably the best method to keep food cool without electricity is a device called the evaporative cooler. Evaporation is the natural change of water from liquid to gas as the water mixes back into the atmosphere. An evaporative cooler is easy to make. And it does not need ice.
如果沒有電，保持食物涼爽的最好方法可能是一種叫做蒸發(fā)冷卻器的裝置。蒸發(fā)是水從液體到氣體的自然變化，因為水又回到了大氣中。蒸發(fā)式冷卻器很容易制造。它不需要冰。
One common evaporative cooler is built as a tall box. Food is kept on several shelves inside. The shelves are made from pieces of metal with many small holes. All four sides of the box are covered with thick cloth. A container of water is placed at the bottom. Another container of water is placed at the top.
一個普通的蒸發(fā)冷卻器是作為一個高盒子建造的。食物被放在里面的幾個架子上。這些架子是用有許多小孔的金屬片做成的。盒子的四面都鋪上厚厚的布。一容器的水放在底部。另一個容器的水被放置在頂部。
The top and bottom of each piece of cloth is placed in the water. This keeps the cloth wet.
每一塊布的頂部和底部都放在水里。這把布弄濕了。
Put the cooler out in the open air, but not in the sun. Air will pass through the wet cloth. This keeps the inside of the box several degrees cooler than the outside air temperature. And this is often just cool enough to keep foods fresh.
把冷卻器放在室外，但不要放在陽光下?？諝鈱⒋┻^濕布。這使得盒子的內(nèi)部溫度比外面的溫度低幾度。而這通常只是為了讓食物保持新鮮。
