Are food preservatives bad for you? - Eleanor Nelsen

翻译人员: 小布 陈 校对人员: Cissy Yun

Food doesn't last.

食物会变质

In days, sometimes hours, bread goes moldy,

几天时间，有时几个小时， 面包会发霉，

apple slices turn brown,

苹果块变成褐色

and bacteria multiply in mayonnaise.

蛋黄酱里的细菌繁殖

But you can find all of these foods out on the shelf at the grocery store,

但你能在商店里的货架上找到这些食物

hopefully unspoiled,

希望是没有变坏的

thanks to preservatives.

多亏了防腐剂

But what exactly are preservatives?

但是到底什么是防腐剂呢

How do they help keep food edible and are they safe?

它们是如何保持食物可食用呢？它们安全吗？

There are two major factors that cause food to go bad:

有两个重要的因素会导致食物变质

microbes and oxidation.

微生物和氧化作用

Microbes like bacteria and fungi invade food

微生物就像细菌和真菌

and feed off its nutrients.

入侵食物，破坏了他们的营养成分

Some of these can cause diseases,

部分细菌会导致疾病

like listeria and botulism.

像李斯特菌和肉毒杆菌

Others just turn edibles into a smelly, slimy, moldy mess.

其它的只是让食物变味，变小，发霉难看

Meanwhile, oxidation is a chemical change in the food's molecules

同时，氧化作用是食物分子的一种化学变化

caused by enzymes or free radicals which turn fats rancid

由酶或者是导致脂肪变臭、食物变色的自由基引起的

and brown produce, like apples and potatoes.

就像使苹果和土豆变成褐色（的自由基）

Preservatives can prevent both types of deterioration.

防腐剂可以防止这两种形式的恶化

Before the invention of artificial refrigeration,

在发明人工制冷技术之前

fungi and bacteria could run rampant in food.

真菌和细菌可以在食物中疯狂地繁衍

So we found ways to create an inhospitable environment for microbes.

所以我们找到了些制造 一个细菌不可繁殖环境的方法

For example, making the food more acidic unravels enzymes

例如，让食物变的很酸来分解酶

that microbes need to survive.

使食物分子能够存活

And some types of bacteria can actually help.

有些种类的细菌其实可以起帮助作用

For thousands of years, people preserved food using bacteria

几千年来，人们用能来保存食物的细菌

that produce lactic acid.

就是可以产生乳酸的细菌

The acid turns perishable vegetables and milk

这种酸让易变质的蔬菜和牛奶

into longer lasting foods,

变得可以长期保存

like sauerkraut in Europe,

像欧洲的德国酸菜

kimchi in Korea,

韩国泡菜

and yogurt in the Middle East.

中东的酸奶

These cultured foods also populate your digestive track with beneficial microbes.

这种人造食物含有的有益分子还能促进消化

Many synthetic preservatives are also acids.

很多合成防腐剂也是酸

Benzoic acid in salad dressing,

沙拉酱里的苯甲酸

sorbic acid in cheese,

奶酪里的山梨酸

and propionic acid in baked goods.

面包里的丙酸

Are they safe?

它们安全吗？

Some studies suggest that benzoates, related to benzoic acid,

有些研究表明与苯甲酸相关的苯酸盐

contribute to hyperactive behavior.

会导致人们的多动行为

But the results aren't conclusive.

但结论并非结论性的

Otherwise, these acids seem to be perfectly safe.

此外，这些酸似乎是非常安全的

Another antimicrobial strategy is to add a lot of sugar, like in jam,

另一种抗菌方法是加大量的糖，例如果酱

or salt, like in salted meats.

或者盐，例如腌肉

Sugar and salt hold on to water that microbes need to grow

糖和盐吸附了分子生长需要的水

and actually suck moisture out of any cells that may be hanging around,

真正的吸干了任何细胞生长需要的湿度

thus destroying them.

因而摧毁了他们

Of course, too much sugar and salt can increase your risk of heart disease,

当然，大量的糖和盐会导致一些疾病的风险，心脏病

diabetes,

肥胖

and high blood pressure,

高血压

so these preservatives are best in moderation.

所以这些防腐剂还是适量为好

Antimicrobial nitrates and nitrites, often found in cured meats,

抗菌剂硝酸盐和亚硝酸盐多存在于熏肉里

ward off the bacteria that cause botulism, but they may cause other health problems.

它们抑制了能导致肉毒杆菌中毒的细菌，但是他们可能会引起其他健康问题

Some studies linking cured meats to cancer

一些研究把熏肉和癌症联系在一起

have suggested that these preservatives may be the culprit.

称防腐剂可能是罪魁祸首

Meanwhile, antioxidant preservatives prevent the chemical changes

同时，抗氧化剂能够防止导致食物产生异味

that can give food an off-flavor or color.

或者变颜色的化学变化

Smoke has been used to preserve food for millennia

千年来，人们用熏制的方法来保存食物

because some of the aromatic compounds in wood smoke are antioxidants.

因为使用木材熏制时产生的一些香味的合成物就是抗氧化剂

Combining smoking with salting was an effective way of preserving meat

在冷冻保存之前，加盐熏制是一种保存肉类有效的方法

before refrigeration.

For antioxidant activity without a smoky flavor,

如果活性抗氧化剂没有烟熏的香味的话

there are compounds like BHT and tocopherol,

有些合成物像BHT（一种常用的抗氧化剂）和生育酚

better known as vitamin E.

就是大家熟知的维生素E

Like the compounds in smoke, these sop up free radicals

就像烟熏中的合成物，这些吸掉了一些自由激进分子

and stave off rancid flavors

避免产生腐臭

that can develop in foods like oils,

可以在一些食物里产生，像油，

cheese,

奶酪

and cereal.

和麦片

Other antioxidants like citric acid and ascorbic acid

其他的一些抗氧化剂 像柠檬酸和维生素C

help cut produce keep its color

通过抑制酶导致食物变黄

by thwarting the enzyme that causes browning.

帮助食物保持新鲜的颜色

Some compounds like sulfites can multitask.

有些合成物，像亚硫酸盐则是有多重功效

They're both antimicrobials and antioxidants.

它们兼任抗菌和抗氧化的作用

亚硫酸盐可能会使有些人产生过敏症状

Sulfites may cause allergy symptoms in some people,

but most antioxidant preservatives are generally recognized as safe.

但是大部分抗氧化剂通常被认为是安全的

So should you be worried about preservatives?

所以你应该担心防腐剂吗？

Well, they're usually near the end of the ingredients list

它们通常被列在食物成分表的最后

because they're used in very small amounts

因为它们的分量很少

determined by the FDA to be safe.

是由FDA（食品药品监督管理局）通过的安全分量

Nevertheless, some consumers and companies

不管怎样，一些消费者和公司

are trying to find alternatives.

正在试图找到替代品

Packaging tricks, like reducing the oxygen around the food can help,

通过包装的设计，例如真空压缩减少氧气有利于保存食物

but without some kind of chemical assistance,

但是没有化学物质的帮助

there are very few foods that can stay shelf stable for long.

很少的食物可以长期保存