Are spotty fruits and vegetables safe to eat

有斑点的水果和蔬菜可以安全食用吗

来源视频

In 2010, $30 billion worth of fruits and vegetables

were wasted by American retailers and shoppers

in part because of cosmetic problems and perceived spoilage.

That's a poor use of about 30% of the produce on the market,

not to mention the water and energy required to grow and transport it,

and the landfill space getting used up by rotting fruit.

So what are those cosmetic problems?

2010年，价值三百亿美元的蔬菜水果

被美国的商家和消费者白白浪费掉，

其中一部分是因为 品相问题和表面的污损。

这些损失就占到了市场上30%的农产品，

更不用说其生长和运输过程中 所耗费的水电了，

连垃圾场也不得不 腾出空间来倾置腐烂的水果。

那么品相问题是什么？

You've probably passed over a spotty apple in the grocery store,

or accidentally sunk your thumb into a mushy patch on a tomato.

These blemishes can doom produce to the trash can.

But what are they anyway,

and are they actually bad for you?

你一定在水果店嫌弃过 带有斑点的苹果，

或是不小心捏到了番茄上塌软的部分。

这些污损注定了这样的农产品要被扔掉。

但它们究竟是什么，

对我们真的有害吗？

Those spots are evidence of an epic battle between plants and microbes.

Like humans, plants coexist with billions of fungi and bacteria.

Some of these microbes are beneficial to the plant,

suppressing disease and helping it extract nutrients.

Others are pathogens, attacking the produce,

still alive as it sits in a store display or your refrigerator

and siphoning off molecules they can use themselves.

The good news is  they're almost never bad for you.

这些污损实际上是微生物侵入植物的证据。

和人类一样，植物生长的环境 也存在着数不尽的真菌和细菌。

有些是对植物有益的，

比如抑制病虫害和增强养分吸收。

其它则是病原菌，能够破坏植株，

即使蔬果被摆上了商品架或者 放入冰箱，它们还有残留，

继续榨取宿主养分以供自己存活。

所幸它们对人体几乎是无害的。

These fungi and bacteria have spent millions of years

developing strategies to overcome a plant's immune system.

But healthy human immune systems are different enough

that those strategies  just don't work on us.

So in a plant, what does this process look like?

这些真菌和细菌已经用了 几百万年的时间

进化出抵御植物免疫系统的能力。

但是由于健康人体的 免疫系统和植物的大相径庭，

它们的抗免疫能力对我们不起作用。

那么在植株上， 这一过程是如何发生的呢？

Microbes can reach plants  in a number of ways,

like getting splashed onto it during watering or fertilization.

Under the right conditions,

the microbes grow  into large enough colonies

to attack the waxy outer layer  of fruit or leaves.

Their target: the delicious sugars and nutrients inside.

This type of pathogen often makes spots like this.

微生物接触植株的方式很多样，

比如在浇水施肥的时候洒落到植株上。

然后在合适的条件下，

微生物繁殖成大块菌落，

并开始破坏水果或者叶片的蜡状表皮。

它们的目标是内部美味的糖分和养分。

这种病原菌通常会导致这样的斑点。

A clump of bacteria drains the nutrients and color from the fruit's cells

making that yellow halo.

It then moves outward,

leaving a black spot of dead cells in its wake.

Each spot, which could contain hundreds of thousands of microbes

is actually caused by a combination of microbial attack

and the host defending itself.

凝块的细菌摄取养分 促使水果细胞发生了颜色变化，

出现黄色的圆形斑点。

之后它们向外扩散，

在待过的地方留下黑斑状的死细胞。

一个斑点里可能有成百上千的微生物，

实际上这是它们入侵和宿主自卫的过程中

共同造就的产物。

For example, this is the bacterial pathogen Pseudomonas syringae.

Once on a tomato,  it enters the fruit and leaves,

multiplies in the space between the cells,

and produces toxins and proteins

that allow it to disrupt  the plant's immune response.

One toxin coronatine makes plants' stomata open up,

allowing bacteria to enter  more freely.

Coronatine also activates pathways leading to chlorophyll degradation,

which you can see as yellow spots.

As the bacteria continue to feed and multiply,

they start to kill off the plant cells.

That explains spots, but what about mushy blemishes?

举个例子，这是丁香假单胞菌。

一旦接触到番茄， 它就会侵入果实和叶子，

在细胞间隙繁殖，

分泌毒素和蛋白质

从而使植株的免疫反应失效。

一旦有毒的冠菌素打开了植株的气孔，

细菌入侵就畅通无阻了。

冠菌素同时还能降解叶绿素，

所以我们才会看到黄色的斑点。

随着细菌不断得到滋养和繁殖，

它们开始杀死植株细胞。

这是斑点的由来，但是 塌软的部分又作何解释呢？

Those are usually caused when the fruit is attacked by microbes

after it's detached from the plant.

If the plant is wounded during transport,

necrotic fungi can infiltrate  through the wound,

kill the cells,

absorb their nutrients,

and leave your food  looking mushy or brown.

Those spots in particular  can taste pretty bad.

You're eating dead  and decomposing tissue, after all.

But you can usually salvage the rest of the fruit.

The non-mushy spots, like the ones you typically see on apples or tomatoes,

are just on the surface  and don't usually affect flavor.

它们通常是在果实被微生物入侵

并且离开后才形成的。

如果植物在运输过程中表面受到破损，

坏死性真菌可以从伤口渗入

杀死植株细胞，

榨取养分，

导致食物看起来 呈褐色或者塌软的样子。

这类斑点尝起来尤其难吃。

毕竟你吃下去的 是坏死和分解后的组织。

但是其余完好的部分 还是可放心食用。

你在苹果或番茄上 常见的没有塌陷的斑点

只是不美观，但并不影响味道。

Of course, microbes that do make us sick, like E. coli and salmonella,

can hitch a ride on vegetables, too.

But because they're not plant pathogens, they don't typically cause spots.

They just hang out  invisibly on the surface.

So it's washing fruit and veggies, not avoiding the spotty ones,

that will help you avoid getting sick.

当然，有些微生物是致病的， 比如大肠杆菌和沙门氏菌，

它们也会搭蔬菜的顺风车。

但是因为它们不是植物病原菌， 所以不会导致斑点。

它们只会无形地附着在表面。

因而正确的做法是清洗蔬果， 而不是避开斑点，

这样才能让你预防疾病。

So the next time  you're at the grocery store,

don't be afraid  to pick up funky-looking fruit.

Some stores will even give you a discount.

Wash them well and store them properly,

as some produce like apples and cabbages will keep in the fridge for weeks.

The spotty ones may not be eye candy, but they're safe and just as delicious.

所以下一次你再去买水果，

请放心挑选看上去很丑的水果。

没准老板还会给你优惠。

只要洗干净它们，合理贮藏，

一些农产品如苹果和卷心菜 是可以冷藏保鲜几个星期的。

带斑点的蔬果也许不美观， 但它们是安全的，而且同样美味。