From Fountain of Youth to Fruit on the Bottom: How Yoghurt Finally Made it Big in America

Speaker 1 Yogurt is a miracle. It's the creamy result of when you leave milk out for too long and juzh it up a little bit.

Speaker 1 I think yogurt is like one of the dreamiest substances that we have to eat in existence.

Speaker 2 I mean, I like yogurt fine, but we live in a world with chocolate. So, I'm definitely not here to diss it.
Yogurt is an extremely popular substance, and rightly so.

Speaker 3 There's fruity yogurt, plain yogurt, Greek yogurt, drinkable yogurt, Icelandic yogurt, frozen yogurt. The list goes on and on.
So who invented this dreamy, infinitely versatile food?

Speaker 3 Where did it come from?

Speaker 2 Fortunately, Cynthia, you are in an episode of Gastropod, the podcast that loves to get to the bottom of exactly these kinds of questions.

Speaker 2 So let's have a look at yogurt through the lens of science and history.

Speaker 3 I am, of course, Nicola Twilley, and I'm Cynthia Graebert. And if you happen to catch any ads for yogurt, it seems like it'll solve all of your health woes.
Where did that come from?

Speaker 3 How did this idea start that it's like this elixir that will bestow immortality?

Speaker 2 The other thing is, like you said, there's a million different kinds. The yogurt aisle stretches half the length of the store.

Speaker 2 But what's the difference between all the different yogurts, like Greek or Australian or Icelandic or even your basic Dannon or Yopla?

Speaker 3 All this, plus yogurt made with the help of some friendly ants. Yes, ants, the insect kind.
This episode was supported in part by the Alfred P.

Speaker 3 Sloan Foundation for the public understanding of science, technology, and economics, and by the Boroughs Welcome Fund for our coverage of biomedical research.

Speaker 3 Gastropod is part of the Vox Media Podcast Network in partnership with Eater.

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Speaker 1 So, my father learned to make yogurt from my grandmother, my maternal grandmother, and he started making it in the 90s. And he has perpetuated the same yogurt starter since then.

Speaker 2 This is Priya Krishna, a cookbook author and food reporter at the New York Times, and of course, a mega yogurt fan.

Speaker 3 Yogurt was a foundational part of Priya's childhood.

Speaker 1 Every week, my dad would stand over the stove, stirring hot hot milk, pouring it into a container. He made one large tub of it in a stainless steel container.

Speaker 1 And then he invented what my sister called personals, which were like smaller individual-sized servings of yogurt.

Speaker 1 And

Speaker 1 this was what we ate. Not a day went by that we didn't have yogurt.

Speaker 2 Most of us buy our yogurt at the store these days, but it's not hard to make at home.

Speaker 3 You just have to warm your milk and then add a little bit of your previous batch of yogurt because Because that bit of yogurt has all the live microbes you need to make yogurt and they'll get right to work and start turning the warmed milk into a new batch.

Speaker 3 This is just what Priya's dad did week after week.

Speaker 1 And I think like the biggest panics that would happen in our house were when we were low on yogurt or where all that was left was sort of the watery curds at the bottom of the pot.

Speaker 1 But he would keep these sort of break glass in case of emergency containers of yogurt in the freezer just in case one of us ate all of the yogurt and there was like nary a tidbit to start the next batch with.

Speaker 1 And so he had all of these contingency plans if there was not starter to do the next batch.

Speaker 2 This level of preparedness was essential because Priya's dad's yogurt was extremely delicious.

Speaker 1 My dad's yogurt, it's sort of an Indian style yogurt, which means it's creamy, but it's also very, very tart.

Speaker 1 And just the way it came out in these really wonderful chunks that defined my dad's yogurt.

Speaker 2 Like I said, delicious and also legendary.

Speaker 1 My dad will distribute his yogurt starter to friends.

Speaker 1 So if someone asks him nicely, he will bring some because there's this idea that, you know, My dad's yogurt starter can make like really pristine yogurt.

Speaker 3 And all those families were so excited about this gift of a yogurt starter because yogurt wasn't just a snack. It was really an important everyday food.

Speaker 1 My mom used it to make righta.

Speaker 3 Raita is a yogurt sauce that served almost every meal in Indian cuisine.

Speaker 1 She would also strain it and use it to make shrikand, which is like this very thick cardamom yogurt dessert. It's like one of my favorite desserts of all time.

Speaker 1 But among many South Asian families, and I know yogurt is essential. It is often not something you buy.
It is something you make. It is sort of an underpinning to our meals.

Speaker 1 You serve yogurt with an Indian meal. It like sort of cools you off.
It functions as sort of a refreshing counterbalance to this food that has often a lot of spice.

Speaker 1 I don't mean heat spice, but just like a lot of spices in general.

Speaker 2 Recently, Priya reported a story on the importance of homemade yogurt among South Asian families and how carefully each family's yogurt starter is preserved.

Speaker 1 And the stories I heard were so endearing. It was like people hiding yogurt starter in their suitcase when they were coming from India.

Speaker 1 Or this one woman told the story about moving cross-country and holding her family's family's turtle in her lap and having the yogurt starter next to her strapped with a seat belt, like in a seat.

Speaker 1 Like the yogurt got its own seat in the car. And that's how important it is to perpetuate the yogurt starter.

Speaker 3 But South Asians aren't alone in their love for yogurt. Today it's popular around the world and it's been popular for thousands of years.

Speaker 2 Basically, for as long as we've had milk and containers to put it in, which is something like nine or ten thousand years.

Speaker 10 So how long have we been eating yogurt? Probably since we domesticated animals to produce milk.

Speaker 3 Veronica Sinat is a professor of food science at the University of Copenhagen, and it seems like the discovery of yogurt was a perfect marriage of domesticated animals, the invention of pottery to hold liquid, and of course, place.

Speaker 2 There's a popular story that the big yogurt breakthrough came when some nomadic tribesperson in Central Asia was carrying some milk in an animal skin pouch, and by the end of a long, hot day on horseback, the milk had turned into sour curds, aka the very first yogurt.

Speaker 3 That's a fun and picturesque story. But most researchers think that isn't how the discovery came about.

Speaker 3 They think it's more likely that the milk was left in a ceramic container outside in the warm sun and microbes just started doing their thing. No jiggling on a horse required.

Speaker 12 Because all you really need in order to create yogurt is you need a milk source and you need bacteria and you need the right climate.

Speaker 12 And so you now had those three things coming together in a very organic way.

Speaker 2 This is June Hirsch. She's a cookbook writer and the author of Yogurt, a Global History.

Speaker 12 You had them take this milk product, they put it outside. They were in the area near Turkey, so it was hot, and they left it out there.
And it curdled, and it thickened, and it coagulated.

Speaker 12 The Turkish word yogurmark, which means to coagulate or to thicken, is really descriptive of what the product was that they got.

Speaker 2 Typically, if you think of leaving milk out on a hot day, you think of it going bad and maybe even making you sick.

Speaker 2 But this coagulated sourness was not only tasty, but also maybe made people feel better.

Speaker 3 One theory about why people latched on to this new tangy, thickened milk that didn't make them sick has to do with my personal plague, lactose intolerance.

Speaker 3 Most people at the time in those regions couldn't tolerate lactose, and something like 70% of all people around the world still can't today.

Speaker 3 Lactose is a particular milk sugar that we humans can digest as babies. It's why we can thrive on breast milk, but most people lose that tolerance as they age.

Speaker 2 Milk is super nutritious. It seemed like it could have been a great food resource, but drinking more than just a tiny bit was and is a fast track to digestive distress for most adults.

Speaker 2 But these early people in what's now Turkey found that they could have a little bit more of this soured, thickened version of milk without wanting to puke.

Speaker 2 And that's because there's about half the lactose in yogurt that there is in milk.

Speaker 3 And that's because that lactose, that milk sugar, is a great food for, yes, microbes. And now you can drink, because the trick to turning milk into yogurt is really microbes.

Speaker 10 And the microbes in it, often bacteria, produce acids and transform that milk through their microbial metabolism into a tangy yogurt.

Speaker 2 These are not just any old microbes, they are two very specific lactose-consuming microbes.

Speaker 10 Yogurt, by definition, contains Streptococcus thermophilus and lactobacillus delbronchi bulgaricus.

Speaker 3 And these microbes do one other important thing other than consuming lactose. As Veronica said, they produce acids.

Speaker 3 And those acids, that acidic taste in the yogurt, it keeps out other microbes that could be toxic to humans. Those are the ones that would just turn milk bad.

Speaker 3 Getting a hold of those particular acidic microbes was really helpful in the days long before refrigeration.

Speaker 10 As you start to milk animals, or maybe you have a herd of animals, you might not be able to consume all the milk in one period of time, right?

Speaker 10 So how are you going to preserve this lovely, nutritious resource? Fermentation, that microbial transformation allows for you to preserve it.

Speaker 10 So you could turn milk into something like yogurt, and that prevents other microbial spoilage organisms from getting in there, essentially preventing your food from rotting or going bad.

Speaker 10 So that could be a major advantage.

Speaker 2 This is truly a microbial blessing. These two microbes made milk both longer-lasting and more digestible.
No wonder people are protective of their starter cultures.

Speaker 3 But, so, where did these incredibly useful microbes first come from?

Speaker 2 This is the trillion-dollar question. No one really knows because these two microbes can be found in all sorts of places in the wild, from human saliva to animal guts to wildflowers and grasses.

Speaker 10 Some people suggest that the microbes in our yogurt that we use today come from animals. They like to live at really warm temperatures, more like mammalian body temperature.

Speaker 10 The question becomes, did it come from the cows or the animals themselves and it was part of their microbiome that kind of transitioned into our fermented foods?

Speaker 10 Or is it part of our microbiome in these lovely warm environments like our mouth or other places.

Speaker 3 We may never know exactly where these two main yogurt bacteria originally came from, but there's another twist in the yogurt origin story, and it's that yogurt wasn't one thing, it was plural yogurts, and each one might have had a slightly different microbial community that was fermenting it.

Speaker 10 Traditional yogurt can have many different types of lactic acid bacteria. microbes that are eating those sugars in the yogurt and then producing lactic acid.

Speaker 10 That could be these true traditional yogurt microbes, but it could be a variety of other species.

Speaker 10 They also might contain some yeasts that might add a little bit of effervescence or different flavor profiles.

Speaker 3 All those different microbes and fungi could really have come from anywhere. It's kind of a tantalizing mystery.

Speaker 3 Veronica studies the ecology and evolution of microbes in fermented foods, and she was curious about the origin of these microbial communities in yogurt.

Speaker 2 What really intrigued her were stories from her colleague Sevki Motlo-Sarikova, who's originally from Bulgaria.

Speaker 2 Sevki told Veronica about yogurt that was created by putting ants in it, which made Veronica wonder, could the microbes in this yogurt have come from ants?

Speaker 10 Sevki had collected stories of ant yogurt that came from Turkey, it came from Bulgaria. We've also collected other stories that come from other Balkan countries.

Speaker 3 So she and her colleagues traveled to a town in Bulgaria where Sevgi's family is from, and they worked with a community to recreate that traditional ant yogurt so they could study it.

Speaker 10 They hadn't actually been making ant yogurt, it seemed like, regularly or potentially even for decades, but many people had living memories of how it was made.

Speaker 2 Ant yogurt turns out to be a seasonal treat.

Speaker 10 This ant yogurt is made as part of a springtime tradition or a spring celebration, religious celebration called the Hildriles.

Speaker 10 And as spring sets in, everything starts moving and growing. And so do the ants.
Their colonies become alive again. They start crawling all over their nest, but also all over the environment.

Speaker 3 From the stories people told Veronica and her colleagues, it seems like people would drop whole ants into warm milk and then bury the container of that milk in the ant colony overnight. But why?

Speaker 3 Why ants? Why the one particular kind of ants that they used?

Speaker 2 So

Speaker 10 why these ones? These ants produce acid. They produce formic acid.
If you disturb them, they'll even start spraying it at you. And you can smell it.

Speaker 10 If you decide to lick your hand, you would certainly taste it, that it's a bit lemony.

Speaker 2 Adding an acid to milk, something like lemon juice, is a known trick to kickstart the fermentation process, whether you're making yogurt or cheese.

Speaker 2 You don't need it, but it helps create the nice acidic environment that the microbes like to work in.

Speaker 10 And I think that might be one of the reasons why they started to think, oh, these are a sign of spring. These ants are acidic.
maybe acidic like the yogurt. Could that be important?

Speaker 10 The ant colony is also warm.

Speaker 10 So if you were to put your hand inside the ant colony, it's like this nice, cozy environment, much like that nice, cozy, warm environment that you would wrap your yogurt in, wrap that blanket around it so it stays warm.

Speaker 10 So it could be something like an incubator. Those are maybe some of the reasons why they chose ants and particularly those ants, because certainly not all ants will work for this fermentation.

Speaker 3 The story of ant yogurt is an interesting bit of cultural history, but Veronica is a scientist.

Speaker 3 She wanted to understand exactly what was going on, what the ants were contributing to the yogurt making process.

Speaker 2 And to do that, she had to make ant yogurt back at her lab in Denmark.

Speaker 10 So the ants are in many different places, actually. And luckily, they were in our own backyard here in Copenhagen.
They're a major fixture of the landscape in these pine forests.

Speaker 10 So it was really easy. We collected the ants from the Danish landscape, brought them back to the lab.

Speaker 3 They actually crushed the ants so they could release anything and everything that was in the ants into the milk. The milk itself was totally sterilized.

Speaker 10 It was this really controlled test of can the microbes and the things in the ants get into the milk and how does that work in that yogurt making process on really this food science level.

Speaker 2 Veronica and her colleagues left the milk with the ants to incubate incubate overnight. And when they came back, it was definitely well on its way to yogurtification.

Speaker 3 It had begun to coagulate. It was a little acidic.
It wasn't fully yogurt, but it was getting there.

Speaker 3 And so then they analyzed the ants themselves and the yogurt to find out what was in the yogurt that hadn't been in the sterilized milk.

Speaker 2 Obviously, the ants had brought acid, that lemony formic acid they're known for, but they'd also brought the all-important microbes.

Speaker 10 The ants bring in lactic acid bacteria. They brought in this really cool bacteria called fructilactobacillus sanfrancisciensis,

Speaker 10 which actually is normally found in sourdough bread.

Speaker 10 The ants also brought in acetic acid bacteria that they seem to keep in their mouths and in their guts and have evolved with for millions of years, likely.

Speaker 3 Veronica was excited to find out that these ants contributed just what was necessary to make yogurt, but it turns out that the ants had another trick up their sleeves, another contribution to the yogurt yogurt making process.

Speaker 3 They dropped off some enzymes, too.

Speaker 10 These enzymes munch on the proteins, break down these proteins into smaller peptides or amino acids, and that's great because the food's more nutritious, but also the other microbes in the microbial mix can use those amino acids for their own metabolism and growth.

Speaker 10 Enzymes can also contribute to the texture of yogurt. So enzymes can cause the casein, this major protein molecule in yogurt.

Speaker 10 It causes the molecules to aggregate a certain way, and then the milk coagulates.

Speaker 2 In other words, ants are basically an all-star yogurt-making machine.

Speaker 3 Of course, you don't need all those ingredients to make yogurt, and you don't need ants in particular.

Speaker 3 In fact, as Veronica said, most people they spoke with in Bulgaria aren't even making ant yogurt anymore.

Speaker 10 So, when other researchers have gone out and sampled all household yogurts around Bulgaria, for example, they don't find any ant microbes in them.

Speaker 2 So ants are probably not the origin of today's yogurt bacteria.

Speaker 2 But Veronica does wonder whether the sourdough bacteria she found in her ant yogurt, whether that might have made its way from ant yogurt into the sourdough starters behind the bread we still enjoy today.

Speaker 10 It's not unheard of to use yogurt in your sourdough starter, but the moral of the story is that the yogurt could be used in different fermentation products like sourdough.

Speaker 10 It could be in the kitchen environment.

Speaker 3 And this isn't the only story of insects helping create delicious foods by bringing along the necessary microbes.

Speaker 3 There's been research in Italy, for instance, showing some of the microbes that can turn grape juice into wine came from wasps.

Speaker 2 And so while, again, no one is saying that ants are the forefathers of all yogurt, What's so cool about the fact that ant yogurt actually works is that it helps show how many different ways humans could have arrived at tangy fermented dairy products.

Speaker 2 Today, we mostly just rely on two microbes, but imagine the variety in the past.

Speaker 3 I still really want a time machine. Anyone out there help me out? But Veronica and June have some ideas about what that variety might have tasted like.

Speaker 10 So there was no single yogurt with a specific flavor. I think it was inevitably more complex than the yogurt you can buy at the grocery store today in its acidity,

Speaker 10 other different profiles. Maybe it had some botanical notes to it.
It depends on who was making it and just how they did it and what microbes they carried with them and carried with their yogurt.

Speaker 12 So depending on the strain of bacteria that you use, you get a very different taste.

Speaker 2 Until someone comes through with Cynthia's time machine, that's as close as we'll get to an ancient yogurt flavor profile or profiles. But what we do know is that ancient people loved it.

Speaker 2 It was a hit and it caught on all over throughout the Balkans, the Middle East, the Caucasus, and Central and South Asia.

Speaker 3 Yogurt was mentioned in lots of ancient texts in lots of different languages, and it was also almost always mentioned as something that was particularly healthy, almost medicinal.

Speaker 2 The classic yogurt is the key to health story may or may not be true, but it is a good one.

Speaker 2 It stars Yogurt, obviously, but also King Francis I, who ruled the yogurt-free nation of France in the early 1500s.

Speaker 12 From what the stories go, he had a sour stomach and an even more sour disposition, and all of the people in his court wanted somehow to get this man some relief feeling that if they could relieve his indigestion perhaps he would not be such a disgruntled ruler and so he reached out to Suleiman the magnificent in the Ottoman Empire and he said we hear you have a doctor who can cure sour stomach That doctor was a Jewish guy who apparently, so the story goes, he hiked all across continental Europe Europe from the Ottoman Empire to France with a herd of sheep, got there and made some yogurt with that sheep's milk.

Speaker 12 He supposedly cured the sour stomach and the chronic indigestion of the French king,

Speaker 12 forever stayed in their good graces,

Speaker 12 improved the health and the well-being apparently of everyone in France because now supposedly he became this lovely benevolent ruler because his stomach wasn't disagreeing with him.

Speaker 2 At the time, Francis proclaimed Yogurt the elixir of life, which you would think would help it catch on in France, but it did not.

Speaker 2 It took many more centuries and a bunch of starfish before yogurt would make it big in the West. That story coming up after this word from our sponsors,

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Speaker 3 We've said that yogurt got big in a pretty significant swath of the world from the Middle East East all the way through Central and South Asia, but it wasn't particularly well known in most of Europe.

Speaker 3 That's why King Francis didn't think of taking yogurt to cure his stomach without some outside intervention.

Speaker 2 In some parts of the world, it makes sense that yogurt didn't get invented. There weren't many milkable animals in North and South America, Australia, and the Far East.

Speaker 2 But Northern and Western Europeans had milk up the wazoo, and that milk would have spoiled without refrigeration too, maybe a little bit more slowly than in the heat of Turkey, but still.

Speaker 2 So, why didn't they invent yogurt?

Speaker 3 It turns out that the climate is key. The particular microbes that make yogurt yogurt, yogurt isn't cheese, it's not sour cream, it's not buttermilk.

Speaker 3 These yogurt microbes not only love heat, they can't live without it.

Speaker 2 They just were never going to be happy in England or Sweden or even France, so those places developed a completely different coagulated milk culture. So, you get butter and aged cheese.

Speaker 2 They need cool temperatures, which meant they weren't great options in the Middle East or Central Asia.

Speaker 3 Northern and Western Europe all also did have their own versions of soured milk, milk that's been lightly fermented and curdled.

Speaker 3 But these were made with different microbes that like the cooler temps in Northern Europe. And the resulting soured milk is a lot less sour than yogurt is.
They have a kind of fresher, milder taste.

Speaker 3 These are like British and Irish claber, creme frache in France, German cork.

Speaker 2 Those milder, lower temperature microbes also, incidentally, eat a lot less of the lactose, the sugar in milk, which may have contributed to making it an evolutionary advantage for Western and Northern Europeans to pass on the mutation that makes them able to digest lactose as adults.

Speaker 3 But the point is that for Western Europeans, yogurt just wasn't a food they were familiar with.

Speaker 3 If they did get a taste, it would have been something super exotic, like the yogurt that the Jewish doctor from the Ottoman Empire had to make for the French king.

Speaker 2 But even more importantly, no one was familiar with what on earth was making any of these fermented foods.

Speaker 2 Despite eating them by the boatload, no one had seen a microbe until microscopes were invented in the 1600s, and no one knew what they did till Louis Pasteur came along in the 1800s.

Speaker 3 Pasteur may have figured out microbes caused fermentation, but he didn't do research on yogurt.

Speaker 3 He did end up creating the Pasteur Institute in France to study diseases and microbes, and the first foreign scientist he invited to come work with him was named Eli Metshnikov.

Speaker 15 He was a Russian biologist who spent the second half of his time in France. He worked in Paris at the Pasteur Institute.
And

Speaker 15 he was very famous not just as a scientist, but he was at the beginning of the 20th century. He was one of the most famous people in the world.

Speaker 3 Luba Vikansky is a science writer and author of the book Immunity: How Eli Metchnikov Changed the Course of Modern Medicine.

Speaker 2 Metchnikov is a big deal in the story of yogurt. He's sometimes known as the grandfather of yogurt.
But his scientific reputation was not built on dairy products.

Speaker 2 He won a Nobel Prize for basically wholesale coming up with the idea of the immune system.

Speaker 15 It wasn't called then at the time, but he developed the very first modern theory of immunity. Until then, there was no notion of immunity in the way we know it exists today.

Speaker 3 In the lab in the late 1800s, Metchnikov was studying starfish larvae. They're transparent, which makes them easier to study.
He noticed that there were cells that were basically digestion cells.

Speaker 3 They ate food for nourishment, and somehow he had the idea that maybe they don't just eat food, maybe they eat harmful things too as a form of protection.

Speaker 15 And he performed one of the most famous experiments in the history of science. He introduced into this tiny larva little pieces of thorns from a rose bush.

Speaker 15 And then he saw the next day that indeed the cells had ganged up on these thorns to protect the little animal.

Speaker 3 They seemed to be a built-in defense system and immune system.

Speaker 3 Metchnikov continued his experiments and eventually discovered that there's a similar, more sophisticated system in humans made of white blood cells that surround and ingest harmful foreign particles.

Speaker 2 This was an amazing breakthrough. It was so ahead of its time, it was ridiculed at first.

Speaker 2 But ultimately, it made Metchnikov famous, and so he got an invitation to come work at the center of the universe for science at the time, the Pasteur Institute in Paris.

Speaker 3 This was an incredibly exciting time in science, and particularly for the Pasteur Institute. Pasteur had just created a vaccine against rabies in 1885.

Speaker 15 And that was like a miracle cure. This was just something that was

Speaker 15 totally captured people's minds, and everybody thought that this was like the beginning, which indeed it was, a new era in medicine.

Speaker 2 Metchnikov carried on researching the immune system at the Institute, but as tends to happen, he was also aging.

Speaker 2 He was in his 40s when he arrived in Paris, but by the time he got into his 50s, he was beginning to feel like, well, not a spring chicken anymore.

Speaker 15 He started to worry about getting old. That was then, I guess, you know, considered old.
And that's how he felt.

Speaker 3 Metchnikov had an idea at the time. This wasn't just his theory, it was kind of a popular theory in medicine.

Speaker 15 It was even, I would say, verging on a medical obsession. It was

Speaker 15 called auto-intoxication.

Speaker 2 The idea was the germs, microbes, in your intestines, were causing you to rot from the inside out. And Mechnikov figured that was probably what was causing aging.

Speaker 15 So he came up with the idea that aging is a disease, that it's a disease that's caused by, you know, harmful, infectious organisms in the gut, and it should be cured like any other disease.

Speaker 15 That was his starting point.

Speaker 3 This belief, this theory, it made him a total germaphobe. He tried every way possible to prevent what he saw as harmful microbes from getting into his intestines.

Speaker 15 He had a burner in the lab and he sterilized everything. He boiled even bananas because he thought that maybe somehow through the skin the germs can get in.

Speaker 15 And when he went to restaurants where waiters would bring, they knew him, they would bring a burner and he sterilized utensils for himself and for his guests.

Speaker 2 But just avoiding bad germs wasn't enough. Metchnikov wanted a cure.
And just like the immune cells he discovered in starfish, he wondered if there might be good germs that could eat the bad ones.

Speaker 2 And that is how yogurt entered the picture.

Speaker 15 Because fermented milk from the beginning of history was known to preserve milk. Like other products rot and spoil and milk doesn't.
It um it becomes sour. So what actually destabilizes it?

Speaker 15 It wasn't known.

Speaker 2 Metchnikov began to speculate that maybe the microbes that fermented the milk to turn it into yogurt were eating the bad ones that would normally make it spoil, keeping milk fresh longer.

Speaker 2 We know today that isn't how it works. As we said, they create an acidic environment that promotes the growth of beneficial bacteria at the expense of nastier ones.

Speaker 2 But Mechnikov didn't know that, and good microbes that could eat bad ones that made things rot was exactly what he was looking for.

Speaker 3 Metchnikov was already familiar with yogurt. As we said, he was from Russia and people in Russia ate a lot of yogurt, and it had been thought to be a particularly healthy food.

Speaker 3 In fact, his first wife back in Russia, she had tuberculosis, and one of the foods he and the doctors gave her to try to restore her health was yogurt.

Speaker 3 It didn't work, she did die, but that didn't turn him off the food.

Speaker 2 The real breakthrough came when a Bulgarian student called Stamen Grigorov brought back some yogurt from his home region to show his professor.

Speaker 2 They found a bacteria in it, one of the two that's in all yogurt today.

Speaker 15 And they made extraordinary amounts of lactic acid, and they call these bacteria Bacillus bulgaricus.

Speaker 3 The professor in Switzerland knew Mechnikov, so he sent him a sample of the yogurt and of the lactic acid bacteria.

Speaker 3 And he also passed along that in Bulgaria there were an unusual number of people who lived until they were over a hundred.

Speaker 2 There were actually only so many centenarians because there were so few accurate records of their dates of birth. But it made for a compelling story.

Speaker 15 And for Meshnikov, it all fitted in together perfectly. Like, here was his theory that aging is caused by microbes in the large intestines and that you can fight it with good bacteria.

Speaker 15 And the good bacteria, for example, there are in yogurt. And here are these Bulgarians who are living proofs of that.
They eat so much yogurt.

Speaker 3 And look at them. So Mechnikov started giving lectures where he shared his new theory about auto-intoxication and the power of yogurt to cure aging.

Speaker 15 He was a big popularizer of science. And he was a very eloquent speaker and he was very passionate.
And journalists loved him. He was sort of like a media person.

Speaker 15 He was probably the equivalent of like Carl Sagan was for astronomy and he was the same for health, you know, and medicine.

Speaker 2 So when he started talking about yogurt, you could imagine that people listened.

Speaker 2 And then came the tipping point, a lecture that Mechnikov gave on the subject of old age and its prevention in Paris in 1904. Luba says that is when the yogurt frenzy really took off.

Speaker 15 And he brought with him an old dog and an old parrot, and the dog looked sort of shabby and this was sort of his way of showing this is w what happens when you have a large intestine full of germs.

Speaker 15 And birds have like almost no large intestine. And the parrot was 70 and it looked very young, sort of and feisty.

Speaker 3 These were visual props that, at least to Metchnikov, proved, so to speak, the ills of toxic gut microbes. Today we know it's useful for humans and dogs to have a large intestine.

Speaker 3 Birds don't have the same type of large intestine because they need to save space to stay aerodynamic. They've evolved different digestive hacks to make up for that.

Speaker 3 But in any case, that wasn't the only thing he lectured on that day.

Speaker 15 He talked about many things, but the one thing that caught on was this maybe mention of yogurt and the Bulgarians who live these long and healthy lives.

Speaker 2 He also said he personally ate yogurt three times a day.

Speaker 15 And it was just picked up by the press without any caveats, without

Speaker 15 any mention that it's a theory, that it's just an idea, basically. And journalists just ran with it.

Speaker 3 The headlines were splashed across papers in Europe and in America. Sour milk is the elixir.

Speaker 3 And quote, pretty ladies and brilliant gentlemen who don't want to age or die, here's the precious recipe, eat yogurt.

Speaker 15 I found clippings from Chicago, from Los Angeles. From the Pasteur Institute, the great Professor Metchnikov comes up with a cure for aging.

Speaker 2 Eating yogurt was suddenly all the rage in Paris.

Speaker 15 So first of all, there were cafes that sold it. Like you could go for your five o'clock yogurt.
And there was like this one cafe on one of the Parisian boulevards that said, come and eat yogurt.

Speaker 15 And following the

Speaker 15 work of the great Professor Meshnikov, it will prevent the disastrous old age.

Speaker 3 Yogurt was also sold in tablets, and there were chocolates that were spiked with yogurt and yogurt bacteria.

Speaker 2 Doctors were recommending it to their patients in extremely generous quantities.

Speaker 15 So the British Medical Journal, for example, wrote in the review: yogurt can be used for an indefinite time time without harmful results.

Speaker 15 If the dose be not too large, one kilogram a day should not customarily be exceeded.

Speaker 3 For American listeners, one kilo is 2.2 pounds of yogurt per day. No, thank you.

Speaker 2 That is, in fact, what many Americans said about yogurt at the time. There was one snippet from the newspaper in Elk Falls, Kansas that I found particularly lovely.

Speaker 2 It says, quote, curdled milk of a peculiar kind made after a Bulgarian recipe and called yagurt is now a Parisian fad and is believed to be a remedy against growing old.

Speaker 2 A correspondent who has tried it says he would prefer to die young.

Speaker 3 And speaking of dying young, Metchnikov did not in fact live forever. He had not cured aging with yogurt.

Speaker 15 Metchnikov died in 1916 and he died at the age of 71. And he thought that if you take all these preventive measures, he believed that people should and could and should live to 150.

Speaker 15 And when he died halfway through to that mark, you know, it was a huge disappointment for many people.

Speaker 2 Metchnikov had been afraid this might happen.

Speaker 15 And he was very worried about all, you know, this harming his theories. And he was talking about how his whole family didn't quite live long and that he started very late with his healthy regimen.

Speaker 15 He made all kinds of explanations, provide all kinds of explanations for why he wasn't going to live till 150.

Speaker 3 Metchnikov may have been a household name in his day, but his fame kind of died out in the decades after he died. That said, the research he did was totally ahead of its time.

Speaker 15 He conducted just absolutely modern and totally pioneering studies of the gut microbiome. And he tried to answer the question, for example, is it essential? Can we live without it?

Speaker 15 And which germs are good, which ones are bad.

Speaker 15 He found that the microbiome changes throughout a person's life. He found that it could be changed by diet.

Speaker 15 He was a very firm believer in preventive medicine, which was he was like a hundred years ahead of his time in everything.

Speaker 15 But I think, in terms of his popular image,

Speaker 15 if he is remembered for anything, it's just for yogurt.

Speaker 2 But even when it comes to yogurt, the Metchnikov-inspired yogurt fad ran out of steam in most of the world pretty quickly. In the US, yogurt fell back off the radar almost completely.

Speaker 2 So, how did we get from preferring death to eating yogurt to entire supermarket aisles devoted to it today? That's coming up after this break.

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Speaker 14 Adele Davis, I have come to describe as the most popular cookbook writer you've never heard of because she sold, by all accounts, millions of dollars worth of her cookbooks over the course of the 20th century and is not someone that I hear anybody talk about.

Speaker 3 Matthew Wolfmeyer is a professor of science and technology studies at RPI and author of the book American Disgust: Racism, Microbial Science, and the Colony Within.

Speaker 14 I got interested in her because she's one of those people who's like an early proponent of yogurt. And

Speaker 14 you can see in the early cookbooks that she's trying to convince people that it's like an edible substance, you know, that like maybe they've heard about it,

Speaker 14 but they've definitely never tried it.

Speaker 2 Adele's books combined nutrition advice with recipes. They were called upbeat, but also sort of patronizing things like, let's eat right and let's have healthy children.

Speaker 2 She got got going in the late 1940s and hit her stride in the 1950s, and by then, most Americans had gratefully forgotten all about Ellie Medchnikov and wouldn't know yogurt if they bumped into it on the street.

Speaker 3 Adele had very strong feelings about nutrition. A lot of her nutrition advice was pretty sound.
She recommended eating whole grains and vegetables and that people cut down on meat.

Speaker 3 She was also, unfortunately, a big proponent of mega-doses of supplements and had some not particularly science-based recommendations.

Speaker 3 She recommended large doses of vitamins that could be and sometimes were harmful for her readers and their families.

Speaker 2 She was a big yogurt fan, in part because she was a milk fan. She thought milk was super healthy and a great alternative to meat.

Speaker 2 But she also did recognize that yogurt had some unique microbial benefits, too.

Speaker 14 The thing that I often think about is like this recommendation that she has that if you're feeling ill that you eat two cups or four cups of yogurt, right?

Speaker 14 That it's like a significant amount of yogurt in order to deal with stomach stomach upset.

Speaker 3 But apart from spooning out cups when they were feeling crappy, Americans didn't know how to regularly incorporate yogurt into their diets.

Speaker 14 And so, in order to kind of convince people that it's worth eating, she's thinking about like ways that you can convey its palatability.

Speaker 14 And part of that is including it in recipes, but some of it is just convincing people that it counts as food. And she's there to kind of bridge the gap conceptually, to like convince you

Speaker 14 it can be eaten and give you some ideas about how it can be eaten.

Speaker 2 Adele not only provided a recipe for making yogurt at home, she also had a recipe for yogurt sauce with grated onion, mustard powder, and Worcestershire sauce to serve with cold cuts, and another one to go with cheese cutlets.

Speaker 3 Neither sound particularly pleasant, to be honest, but Adele's story highlights two main points about most of America at the time.

Speaker 3 Okay, maybe more than two, because first, food sounds pretty terrible back then. But also, most Americans were one, not familiar with yogurt, and two, didn't really have easy access to it.

Speaker 14 Even Davis, when she's talking about like, where would you find yogurt, she's recommending people go to their, you know, nearby European grocery stores, that it's not going to be something that you'll find at a mainstream grocery store.

Speaker 2 At the time, yogurt was definitely something you'd only find at the quote-unquote ethnic food store.

Speaker 2 It was something that Greek or Armenian or Eastern European immigrants would make and sell to their own community.

Speaker 3 One of those immigrant families, they were Armenians who came to the U.S. in the early 1900s and they moved to Massachusetts.

Speaker 14 It starts with Sarkis and Rose, who are the father and mother of this family, and

Speaker 14 they start an intensely local yogurt distribution network.

Speaker 2 Rose literally made the yogurt at home on the stove, the way she and her family always had.

Speaker 14 In the beginning, it's just plain yogurt, right? And they tell the story that Rose brought the basilis to to start the yogurt from Turkey when she emigrated.

Speaker 3 Rose and Sarkis Kalambosian had a son named Bob, and Bob said his parents used to drive around to deliver yogurt to Armenians living in the area and to bring containers to ethnic stores in Boston.

Speaker 3 He also remembered bringing yogurt to school with him in the very white town of Andover where his family first lived.

Speaker 14 And so he brings it to school to share with people, and his teacher uses it like as a moisturizer, right? Like she puts it on her face in order to like see if that's that's what you do with it.

Speaker 2 Evidently Bob's teacher was not an Adele Davis fan. In any case, Bob eventually joined the family business and worked on expanding it.

Speaker 14 One of the challenges that you can see is they're really trying to figure out how to make it palatable for mass consumption.

Speaker 14 And so part of what they embark on is sweetening it up, putting fruit into it.

Speaker 3 And when they did that, sales just took off. Americans vastly preferred the fruit-based yogurt over the plain kind.

Speaker 2 Colombo yogurt even started making TV ads to promote their yogurt to a whole new audience.

Speaker 18 Hi, I'm Bob Columbosian and this is my wife Alice. This is my mom, Rose Columbosian.
She invented Colombo Yogurt in our kitchen in 1929. The kitchen, it was right about here.

Speaker 18 My mom cooked yogurt in a big bucket. It was this big.
My brother fell in the bucket once.

Speaker 15 We threw that bounce away.

Speaker 3 But Colombo yogurt wasn't the only one on the market at this point.

Speaker 2 One of the earliest yogurt entrepreneurs, a Svardic Jew called Isaac Carrasso, had started a business selling yogurt in Barcelona in the early 1900s.

Speaker 2 He'd grown up in Greece eating thick, strained Greek yogurt, and when the Metchnikov yogurt fad got going, he decided to make a business out of it.

Speaker 3 At the time, he was living in Spain, and he decided to call his company Denone. It was from a nickname for his son Daniel, little Daniel.

Speaker 3 Originally in the 20s, Isaac sold his yogurt in pharmacies as a health food. He died in the 30s, and and Daniel took over.

Speaker 2 In the 1940s, Daniel decided to leave Europe for obvious reasons. He settled in the Bronx and he renamed the American arm of his company Dannon to try to make it more appealing to Americans.

Speaker 2 But even with the new name, the yogurt itself was not flying off the shelves.

Speaker 12 Americans weren't taking to it. So he figured he had to do something.

Speaker 12 Now he took on a partner, Juan Metzger, and together they came up with a number of innovations, but the first and most groundbreaking was they added fruit.

Speaker 3 This was the same move Colombo made to appeal to Americans.

Speaker 3 Both companies had realized they needed to make the yogurt sweeter and more desserty, less tangy, less kind of weird and ethnic, at least to American taste buds at the time.

Speaker 2 But even with fruit and sugar added, and with Adele Davis's enthusiastic backing, it wasn't until the 1970s that yogurt truly hit its stride in the U.S.

Speaker 14 And that is really tied to the health food movement in that moment. It's tied to kind of national distribution networks.
But, like, the 1970s marks like a real shift in American consumption of yogurt.

Speaker 3 America in the 1970s was going through a lot of changes. As Matthew said, more brands were becoming kind of national brands.
Supermarkets were getting bigger and bigger.

Speaker 3 Also, people were, as he said, obsessed with health. A few hippie-crunchy ideas were going mainstream.
And so, Dannin took advantage of this by bringing back Mechnikov's legacy.

Speaker 12 It was their ad that appeared in the 1970s that showed a Soviet Soviet Georgian man who was certainly over a hundred years old in appearance.

Speaker 19 In Soviet Georgia, there are two curious things about the people.

Speaker 20 A large part of their diet is yogurt, and a large number of them live past 100.

Speaker 12 And they said, do you want to know why the people in this region live, many of them, past 100?

Speaker 2 They eat a lot of yogurt.

Speaker 20 Of course, many things affect longevity, and we're not saying Dannon yogurt will help you live longer.

Speaker 2 But Dannon is a natural, wholesome food that does supply many nutrients at this point yogurt had essentially been made into dessert to suit American palates but it was still being marketed as a health food and of course healthy is often code for it will help you lose weight so yogurt really finds one of its early markets in women who are dieting.

Speaker 3 Over the decades since the 70s, yogurt has continued to be marketed as a food that will make you healthy, but the arguments change based on the latest health fads.

Speaker 3 Dannon launched their Activia line in Europe in the 80s and in America in the 2000s, and this one focused on yogurt's microbes and their relationship to gut health.

Speaker 1 I remember my aunt used to buy Activia because of those Jamie Lee Curtis commercials saying it was good for your gut. Okay,

Speaker 2 you were stressed, a lot of junk food on the go, and you were a little irregular, sluggish. My daughter needed Activia.

Speaker 23 Help get your system back on track. Activia with Bifidus Regularis helps regulate your digestive system.

Speaker 3 When it comes to those microbes, of course, fermented foods are good for your gut. We talk about that all the time on Gastropod.
Doesn't have to be yogurt.

Speaker 3 There are lots of great fermented foods out there: miso and sauerkraut and pickles and all sorts of things. Yogurt's good, too.

Speaker 2 Activia was always a little thin and drippy for my taste. But if you, like me, prefer your yogurt on the other end of the texture spectrum, well, don't worry.
Greek yogurt is here for you.

Speaker 2 Greek yogurt is strained after it's fermented to make it even thicker and more tart.

Speaker 12 Why did it catch on? Very simple. It has much less sugar in it.

Speaker 12 And so it became very popular for people who were on the keto diets and the paleo diets because it was really much lower in carbohydrates. So it was pretty much a simple reason for it.

Speaker 12 It was perceived as healthier.

Speaker 3 And today the fat is not just to avoid carbs, but also to seek out protein. And there's yet another yogurt for the protein-obsessed these days.

Speaker 10 Icelandic provision skirt.

Speaker 22 It's like yogurt, but packed with more protein and less sugar. And that's why we've been eating skirt since we were Vikings.

Speaker 12 There's a yogurt to appeal to every single taste and style.

Speaker 1 100%.

Speaker 1 I'm still out here in grocery stores looking at the new brand of yogurt. The obsession will never fade.

Speaker 2 These days, yogurt is big business almost everywhere. It's made it in America, and it's still beloved in its traditional homelands.
It's proven adaptable to all sorts of palates and cuisines.

Speaker 1 In America we're used to like scooping our granola and berries on top of our yogurt. In other countries it's used as a sauce.
In India you know we use it in all of these types of dishes.

Speaker 1 I do feel like it's, you know, a cross-cultural food that speaks many languages.

Speaker 3 Yogurt is compatible with a lot of different cuisines and also it can be both sweet and savory.

Speaker 3 I personally love to turn yogurt into like a sauce for fish with dill and garlic, while my spouse prefers his with maple syrup. Priya enjoys it both ways every single day.

Speaker 1 I have it in the morning in my, I make like a smoothie for myself, and I always put that yogurt in there.

Speaker 1 And then I have it as an afternoon snack, either two ways, either with chocolate chips or with a drizzle of olive oil and salt and pepper.

Speaker 2 Thanks this episode to Priya Krishna, June Hirsch, Matthew Wolfmeyer, Luba Vikonski, and Veronica Sinot. And also to our favorite microbe expert, Ben Wolf, for advice.

Speaker 2 We have links to their work on our website, gastropod.com.

Speaker 2 And in case you're having a meltdown because we didn't discuss Froyo, never fear, our dearly beloved supporters will get the full scoop in their newsletter.

Speaker 2 Get yourself on that list by signing up at gastropod.com/slash support.

Speaker 3 Thanks, as always, to our fabulous producer, Claudia Guy. We'll be back with a brand new episode in two weeks.
Till then.

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