Two reasons why food become spoild

Everyone knows food can become spoiled—go bad and become inedible. Usually, the cause is harmful bacteria that grow naturally in food. So, one of the best ways to prevent food from spoiling is to slow down bacterial growth. But how do you do that? Well, what influences how fast bacteria grow? Mainly, it’s temperature and moisture. So if you want to prevent food spoilage, you need to slow bacterial growth by controlling these factors.

Why’s controlling temperature so important? Because the bacteria that cause food spoilage grow fast at warm temperatures and more slowly at cooler temperatures. When your food is kept cool, it lasts longer, right? For example, fresh fish left out in the sun on a warm day will spoil in a few hours. But if you freeze the fish, it will keep for months and months, right? That’s because low temperatures drastically slow down bacterial growth.

Now, I said that moisture’s another factor you need to control. And every living thing needs moisture, and bacteria are no exception. Food that’s high in water content provides the moisture that bacteria need to grow. Let’s, uh, let’s compare two different kinds of milk, okay? Let’s compare regular liquid milk with dried, powdered milk. Regular milk spoils quickly, right? But milk in powder form can be stored quite a long time…in fact, for years. Of course, bacteria are present in powdered milk too. But what’s different between powdered and regular milk is the water content. Powdered milk has had the water, the moisture removed, and without moisture bacteria can’t grow. And this isn’t true just for milk; just about any fresh food will spoil more quickly than a dried food.

食物变质的两个原因 

每个人都知道食物会变质——变坏，变得不能吃。 通常，致病原因是食物中自然生长的有害细菌。 因此，防止食物变质的最好方法之一就是减缓细菌的生长。 但是你要怎么做呢?那么，是什么影响了细菌的生长速度呢?主要是温度和湿度。 因此，如果你想防止食物变质，你需要通过控制这些因素来减缓细菌的生长。  

为什么控制温度如此重要?因为导致食物腐败的细菌在温暖的温度下生长得快，而在较低的温度下生长得慢。 当你的食物冷藏时，它可以保存更长时间，对吗?例如，在温暖的日子里，新鲜的鱼放在阳光下几个小时就会变质。 但如果你把鱼冷冻起来，它可以保存好几个月，对吧?这是因为低温大大减缓了细菌的生长。  

我说过湿度是另一个需要控制的因素。所有的生物都需要水分，细菌也不例外。 水分含量高的食物能提供细菌生长所需的水分。 我们来比较两种不同的牛奶，好吗?让我们比较一下普通的液体牛奶和干奶粉。 普通牛奶很快就坏了，对吧?但是粉状的牛奶可以储存很长一段时间，实际上是好几年。 当然，奶粉中也有细菌。 但奶粉和普通牛奶的不同之处在于含水量。 奶粉中含有水分，水分被去除，没有水分细菌就不能生长。 这不仅适用于牛奶;几乎任何新鲜的食物都会比干燥的食物坏得更快。