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  • Hi, I'm Emily from MinuteEarth,

  • and under no circumstances would I eat my own baby,

  • but lots of other animals would, and do.

  • Coming up: more about that.

  • But first, three very short stories

  • about the weird stuff we humans eat.

  • Like, for example, spoiled food.

  • Some of our favorite foods are closer

  • to this... than this.

  • That's because coffee, bread, cheese, beer, even chocolate

  • are all home to millions of microbes.

  • In fact, these foods only acquire the tastes, smells, and textures we love

  • because of tiny bacteria and fungi.

  • The vast majority of microbes, about 99%,

  • are actually quite harmless to humans. But the other 1% are

  • nasty enough that our ancestors, and the ancestors of

  • various other mammals and birds, evolved a natural repulsion to stuff that

  • might harbor nasty germs. In general, we think

  • rotten stuff looks and smells disgusting. Which,

  • considering what's at stake, isn't overly cautious.

  • Fortunately, if friendly microbes get to our food first,

  • they can keep the bad guys at bay.

  • Meats left out on the counter provides the perfect conditions for pathogens

  • to florish. It's warm, moist, and protein-rich,

  • just like our bodies. But with some micro-management,

  • adding lots of salt for instance, we can help harmless salt-tolerant

  • microbes outcompete their dangerous but salt-sensitive

  • relatives. A few unrefrigerated months later,

  • we get salami, rather than "salmonelli."

  • Our ancestors stumbled on this kind of controlled

  • spoilage thousands of years ago, either by lucky

  • accidents, or out of serious desperation. And we humans have

  • been intentionally spoiling food ever since.

  • Not only to keep our food safe to eat, but also because the

  • microbes we culture can transform it almost magically

  • into awesome deliciousness. Yeast,

  • for example, gorge on the sugary starch in bread dough,

  • then burp out carbon dixoide that helps give loaves their lift.

  • In a more exotic transformation, bacteria and fungi

  • take turns munching on piles of cacao,

  • mellowing out bitter polyphenols, and helping create the

  • complex and delicious taste of chocolate.

  • And deep in cheese caves, mold spores

  • populate small holes and cracks in soon-to-be blue cheese,

  • digesting big protein and fat molecules

  • into a host of smaller aromatic and flavor compounds that

  • give the final product its smoothness and rich, funky

  • flavor. But to some, stinky cheese is about as

  • appetizing as licking someone's toes. Which isn't that

  • far off, since the bacteria that make some

  • cheeses super stinky are the same ones that cause foot odor.

  • Yum?

  • Even so, these flavors tend to grow on us,

  • not just literally, not also figuratively.

  • The more we're exposed to particular microbial funks, which

  • can even start in the womb, the more we tend to like them.

  • As a result, people around the world have some very different

  • ideas about how to microbify foods.

  • But every culinary culture involves fermentation in

  • one way or another. If we didn't let food spoil just a little bit,

  • we'd have no sauerkraut, soy sauce, pickles, or

  • prosciutto. Not to mention kefir, kimchi, kombucha,

  • koumiss, katsuobushi, and plenty of other delicacies that

  • don't start with "k." What's more, spoiled food

  • may well have changed far more than our tastes. Historical

  • evidence suggests that when our ancestors gave up their wandering ways and

  • settled down to grow grain, it was likely for love of either bread,

  • or beer. Whatever the case, one thing is clear:

  • without the help of friendly fermenting microbes, we humans would be

  • terribly uncultured.

  • So, spoiling our food actually helps keep it good,

  • but we've also come up with another, cleaner way to keep food fresh.

  • Check it out!

  • Food is delicious, not to mention

  • kind of important for life. But food also goes bad.

  • So humans have invented many ways to preserve it to eat later,

  • or far from where it was harvested.

  • Some of these methods require unhealthy chemicals, or

  • degrade the food's nutritional value. But luckily, freezing can

  • preserve food with most of its nutrients, well, frozen in

  • place. The important part is that most chemical and biological

  • processes run slower at lower temperatures. Which means that

  • if you cool food a lot, enzymes and bacteria and

  • fungi in the food get too cold to decompose it. That's why food

  • lasts longer in the freezer than in the fridge than on the counter.

  • Freezing, however, wasn't

  • always an easy task. Especially before fridges were invented.

  • It's not that freezing food is a new idea.

  • I mean, people who live in cold places have

  • done it by default for thousands of years. But things got

  • messy when we started creating artificial

  • winter to freeze food in warmer climates. Early

  • freezers were basically rooms full of salty ice,

  • which, while they could freeze food, took many hours

  • or even days to do so. A slow

  • freeze gives fluid within cells the time to

  • stack up into big ice crystals. Since water expands

  • when it freezes, the sharp edges of these crystals poke

  • holes through the walls of the cells. And when the food thaws,

  • the fluid leaks out. Gross! Even grosser, bird's eyes.

  • Clarence Birdseye, to be precise. An American entrepreneur who lived in

  • Arctic Canada in the 1910s, Birdseye noticed that

  • when Inuit people went ice fishing in −40°,

  • windy conditions, their catch froze almost immediately.

  • When cooked later, the fish tasted fresh. Birdseye realized

  • that the Arctic frozen foods were tasty BECAUSE

  • they froze quickly and formed smaller ice crystals that didn't

  • damage the cells. Inspired, he went on to develop

  • a process to quickly freeze food by pressing

  • small packages between metal plates chilled to 40° below zero.

  • Combined with clever marketing, this allowed

  • Birdseye to bring Arctic winter to the rest of the world, and to

  • almost single-handedly jumpstart the modern market for frozen

  • foods. You probably even have your OWN freezer,

  • a marvellous device cold enough to quick-freeze almost

  • any food you put in it. In other words, the North Pole

  • in your kitchen.

  • Freezers aren't the only food-related gift that northern climes have brought us.

  • They've also given us

  • delicious reindeer meat.

  • So, why don't Americans eat it?

  • In North America, we tend to think of reindeer once a year:

  • as semi-mythical flying creatures that pull Santa's sleigh around the

  • world. Yet not only are reindeer realif things had

  • gone a little differently, we might be regularly chowing down

  • on Blitzen-burgers! That's because when the

  • United States bought Alaska from Russia in the late 1800s,

  • American entrepreneurs saw an opportunity to replicate

  • Russia's long-established reindeer-herding industry,

  • and started shipping domesticated reindeer over to Alaska.

  • But it turns out that reindeer are kind of naughty! Entire herds

  • disappeared into the vast Alaskan landscape,

  • where they died or ran off with the area's native wild reindeer.

  • Reindeer herders in Europe and Russia had similar problems,

  • but with a 3000-year head start, their experience

  • gave them a keener sense of where their animals might wander.

  • Something else that kept reindeer from taking off in North America

  • was cows. Yes, cows.

  • Despite lots of reindeer product marketing, Americans already

  • had meat that they liked. They bought thousands of times more

  • beef than reindeer each year.

  • Yet the cattle industry still lobbied hard against reindeer, even getting some

  • local laws passed that prohibited its sale entirely.

  • Times were tough for the reindeer industry. And then,

  • the Great Depression struck. As people's incomes plummeted,

  • so too did their interest in trying exotic reindeer meat.

  • Many reindeer herders, unable to recoup their costs, left their

  • animals to wander at will, and within 20 years, over

  • 90% of these reindeer succumbed to overgrazing,

  • predators, and the call of the wild. Today, a very small

  • reindeer-herding industry still exists in far northwest

  • Alaska. But most of the meat is eaten locally, and new

  • challenges, like a warming climate that can trap reindeer food under

  • a thick layer of ice, are making it even tougher to herd the

  • creatures. So, for most of us, reindeer will

  • probably remain relegated to Santa's sleigh.

  • Rudolph with his nose so bright won't be on your

  • plate tonight.

  • Whether or not you think it's weird to eat reindeer meat depends on where you live,

  • and whether or not you think it's weird to eat your own babies

  • largely depends on whether or not you're a hamster.

  • Sometimes, a hamster mom looks at her adorable little babies and is like, I just wanna

  • gobble you up. Except, not in a cute way. More in like a,

  • [devil voice] "I'm actually about to eat you" kind of way.

  • And hamster moms aren't alone. Pigs,

  • bugs, birds, snakes, primates, and fish all

  • occasionally nom on the next generation.

  • Which is... weird! Not just because we

  • humans consider it deeply wrong to eat our own babies,

  • but also because making babies is the primary goal of virtually all life.

  • So eating them, and the genes they carry, seems like the

  • ultimate act of self-defeat. But self-defeating

  • impulses have a pretty straightforward way of dying out.

  • So the fact that species across the animal kingdom

  • occasionally cannibalize their young suggests that it can

  • sometimes be a successful strategy.

  • For instance, hamsters appear to use baby-eating as a form

  • of crowd control. Females with litters of 8 or 9 pups

  • eat 2 of them on average. And when scientists

  • have tried adding a couple pups to the litter, the hamster

  • moms eat 4. But removing a few of the

  • pups the day they're born pretty much stops the cannibalism

  • before it starts, suggesting that a hamster mom might

  • eat her young to keep her litter small enough that she can

  • provide for the survivors and ensure they grow up to pass on their genes.

  • Other critters, like the long-tailed sun skink, chown down on

  • their babies only in emergencies. When

  • predators repeatedly threaten to eat the mother's eggs, she beats

  • them to it and eats them all herself, which actually

  • makes sense. If the eggs are doomed to

  • become someone's lunch, making them HER lunch helps

  • prepare the momma skink for another round of reproduction.

  • And sometimes, kids, you know,

  • get in the way. So, they just have to go.

  • The male sand goby fertilizes eggs from multiple females

  • over a short period of time, and cares for them all

  • together in one nest.

  • In order to mate again, he has to wait for all his eggs to

  • hatch. So, he sacrifices the slow-pokes

  • to free himself up for more baby-making.

  • In short, for critters

  • across the animal kingdom to maximize the resources,

  • energy, and opportunities they need to pass on their genes,

  • sometimes it does make sense

  • to order off the kids menu.

  • That's what I'd call a

  • not-so-happy meal.

  • Thanks for watching!

Hi, I'm Emily from MinuteEarth,

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MinuteEarth Explains: Food

  • 10 1
    joey joey に公開 2021 年 04 月 22 日
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