英语时差:我们为什么冷藏水果和蔬菜
Why We Refrigerate Fruits and Vegetable Everyone knows you should put spinach and berries in the refrigerator, but exactly how do cooler temperatures keep most fruits and vegetables from spoiling rapidly? Spoilage is inevitable, but refrigeration slows it down in two ways. First, cold temperatures interfere with the growth of microorganisms that harm food, such as bacteria, mold, and yeast. In order to grow, any microorganism that could damage fruits or vegetables needs food, a favorable moisture content, and a favorable temperature. Obviously, it is impossible to eliminate a food source for these microorganisms, so other factors that facilitate their growth must be eliminated. We refrigerate food to keep bacteria, yeasts, and molds from the favorable temperature they need to grow. The moisture-control available in many refrigerators also helps slow the deterioration of foods, so that two of the three favorable situations for microorganism growth are eliminated. Though the microorganism growth is slowed down at low temperatures, it still can occur at the 38 degrees of an ordinary refrigerator. Hence, the mold that grows on forgotten leftovers in the back of a refrigerator. The second benefit of refrigeration is that it slows down the food’s own natural processes that lead to ripening and eventual decay. For fruits and vegetables, the very chemical processes that cause plants to grow and ripen also cause them to rot. In effect, refrigeration helps save the plant tissue from itself. Keeping these foods at low temperatures dramatically slows this aging process.
