A future without food poisoning? with Emma Bryce and Nicola Twilley

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2:34Elevate your kitchen this summer. Go to quince.com slash tedhealth for free shipping on your order and 365-day returns. now available in Canada too. That's Q-U-I-N-C-E dot com slash TED Health for free shipping and 365 day returns. Quince.com slash TED Health. This is TED Health, a podcast from TED and I'm your host, Dr. Shoshana Ungerleider. Before we get started, I need to confess something about myself. I have a weird thing about food safety. I'm that person who's very serious about expiration dates. I get nervous about food that's been sitting out on the counter, and I'm deeply suspicious of leftovers when the timeline feels a little fuzzy.

3:20And yes, my family and friends make fun of me for it all the time. They tell me I'm being dramatic. They say it smells fine, that people have been eating food like this forever, and I just need to relax. And maybe they're right. But maybe this is also what happens when you're a doctor who's seen some truly awful cases of food poisoning. I've taken care of lots of patients who started with what seemed like a simple stomach ache and ended up hospitalized, wondering how a regular meal turned into a medical emergency. And I have to tell you, once you see that up close, it's hard to unsee it. Your lunch stops feeling quite so simple.

4:00Food is supposed to nourish us. It's tied to comfort, culture, celebration, and connection. But it's also biology. It's microbes and the immune system and supply chains and decisions being made far outside of our kitchens. Most of the time, all that works so well that we barely notice it. But when it doesn't work, that's where the real tension lies. On the one hand, we live in a world where food feels safer and more abundant than ever. On the other, foodborne illness is still very real. And the systems we rely on to keep our food safe and fresh and available are far more complex than most of us realize.

4:40So today we're diving into the TED archives with two talks that approach food safety from very different angles. One zooms way in, down to the microscopic level, and shows how easily things can go wrong when harmful pathogens slip through. The other zooms way out, looking at the massive global infrastructure that keeps our food cold, fresh, and moving, and asking what that costs our health and our planet. These talks invite us to think a little differently about what it really means to keep food safe, and how much responsibility we place on systems that we rarely stop to question. First up, we're taking a really, really close look at the way your body reacts when these pesky little microbes sneak into your diet in the most unexpected ways.

5:30Here's your TEDx lesson of the day. Somewhere on a farm in Iowa in 2010, a hen lays an egg. In just a few short weeks, this egg will be part of a massive infection event. Thousands of people will fall ill, millions of eggs will be recalled, and several egg industry titans will ultimately land in jail. all thanks to a microscopic but mighty bacterium. Salmonella infects millions worldwide each year, causing fever, stomach cramps, and diarrhea. And these effects can be extreme. Salmonella is the leading cause of hospitalizations and deaths from food poisoning. So let's follow this microbe to find out how it makes so many people sick.

6:10We begin in the chicken's digestive tract, a major source of all salmonella infections. In chickens, salmonella bacteria often go undetected, allowing them to spread to eggs, either through the developing yolk or by passing through feces, which can then contaminate shells. Under unhygienic farming conditions, this salmonella-laden feces may also infect or contaminate other animals and crops, causing various food-linked outbreaks. Meanwhile, chicken meat can be exposed to intestinal salmonella during processing. On its journey from farm to plate, the microbe can survive extreme cold, wet, and dry conditions.

6:48However, once it moves into a human body, salmonella reveals its true talents for survival. The first hurdle is the stomach. Here, most bacterial invaders are killed off by stomach acid. But salmonella cells can detect acidic conditions, which triggers the production of acid-shock proteins. These molecules shield the bacteria from damage just long enough for it to pass into the intestines. Salmonella then faces the next gauntlet, as intestinal cells swiftly unleash microbe-destroying immune cells. But once again, the bacteria detect these changes with inbuilt sensors. And embedded within Salmonella's genome are pathogenicity islands, clusters of adaptive genes that launch the next phase of attack.

7:32They signal the construction of a specialized system that resembles a needle and syringe. Within seconds, it injects molecules called effector proteins into the intestinal cells, causing them to change their structure and swallow up the salmonella. Once inside, salmonella can then exploit the cell machinery to replicate and spread. But these invaded intestinal cells don't go down without a fight. As soon as this breach begins, they release cytokines, chemical messengers that prompt the immune system to launch into action. Fleets of white blood cells seek out and destroy salmonella microbes and infected cells.

8:10This inflammatory response is also what leads to symptoms like abdominal pains and fever. And it further damages the breached intestinal cells, limiting their usual ability to absorb water. So, whatever's in the digestive tract gets released in watery diarrhea. While this inflammatory response may feel unpleasant, it effectively purges salmonella from the body within two to seven days for most people, without the need for antibiotics. But there are times when a salmonella infection may require more treatment. It can lead to severe dehydration, particularly in children and older patients. And in some unusual cases, salmonella can continue to spread through the body, hiding inside immune cells, invading other organs and tissues, and even poisoning the blood.

8:56These cases occur if a person is infected by a rare but powerful type of salmonella called S-typhi. Unlike other strains, S-typhi doesn't infect chickens. It spreads from person to person, mainly via poor sanitation and untreated drinking water. Although it's uncommon in many parts of the world, typhoid fever, the disease that S. typhi causes, still kills over 100 ,000 people yearly. Thankfully, there are vaccines to prevent infection by S. typhi. To avoid milder variants, there are steps that everyone can take, like washing your hands, avoiding unpasteurized milk, and cooking meat and eggs thoroughly.

9:33Cookie dough should be off-limits. Raw eggs and flour both carry a salmonella risk. And there are ways to stop salmonella at its source. Investigations into the outbreak in 2010 revealed one company's dark history of unhygienic farming conditions, bribery of health officials, and mislabeled eggs. Since then, the United States has taken steps to put stricter regulations in place. In Europe, many countries have successfully reduced salmonella by requiring testing on farms and before products reach shelves. But there's still work to be done. if we want to stop the spread of this incredibly crafty pathogen.

10:11This TEDx lesson was created by Emma Bryce and directed by Denise Spoletak, narrated by Christina Greer. For me, that lesson was a useful reminder that food safety isn't abstract. It shows up in everyday ways, like feeling sick, missing a few days of work or school, or even needing medical care. And for some people, including kids, older adults, and those already managing health issues, the effects can be more serious. It also brings the focus back to prevention, which so often depends on things going right long before food ever reaches us, along with small familiar choices most of us make without much thought, like washing our hands, cooking food all the way through, paying attention to how food is handled at each step, from production to our own kitchens.

11:02Our second talk zooms out to a system we depend on constantly, often without even noticing it. Refrigeration. It's one of those modern miracles that makes it possible for us to be bolder and more confident with the food on our plate. It's also a prompt for us to consider how to be smarter and more sustainable about the future of eating. And now, Nicola Twilley. Picture Earth's icy places. Mountain glaciers, Siberian permafrost, the poles. This is the cryosphere, the frozen part of the world. Now, picture your fridge. It's a white box, maybe stainless steel, maybe messy, maybe pristine, maybe full, maybe empty.

11:50Regardless, it is just the tip of the iceberg. because if you live in the developed world, your fridge is connected to an entire network of thermal control. It's called the cold chain, and it brings nearly three quarters of everything you eat from the farm to your table. It's also massive. Add all those refrigerated warehouses, shipping containers, trucks, supermarket cabinets together, and this artificial cryosphere is more than 700 million cubic meters. It's a new Arctic. And unlike the real one, it's growing fast as people all around the world get their first fridge and join the cold chain themselves.

12:43A little more than a decade ago, I realized that even though I'd been writing about, thinking about food for years, I had never set foot inside this vast artificial cryosphere we'd built for our food to live in. So I put on my thermal underwear and set out to explore. And what I discovered is that refrigeration isn't really about cold. It's about freshness. But also, once you have a fridge, every food problem seems like it can be solved by cold. take the avocado the avocado is a tropical fruit it has a short shelf life and it is beloved in all kinds of places where an avocado tree would never grow the avocado can only travel thousands of miles and remain fresh and delicious rather than shriveled and rotten because of refrigeration Once it's harvested, an avocado, like a human, only has a certain number of breaths it can take before it dies.

13:49If you chill it, it breathes more slowly and so it lives longer. Yes, fruit and vegetables have better anti-aging tech than we do. Right now, if you go to a supermarket in Amsterdam, the avocados on the shelf are likely from Kenya. Kenyan production of avocados quadrupled between 2010 and 2020. The quantity of avocado eaten by Dutch people quadrupled during roughly the same time span. The two are not unrelated. What's also related, avocados with other fruits and vegetables and together with cut flowers are now Kenya's largest source of overseas revenue. They've overtaken coffee, tea, even tourism.

14:34But the majority of that export produce comes from just a few large farms, several of which are owned by multinational corporations, because they are the ones that have the resources to install and maintain expensive refrigeration equipment. Meanwhile, the avocado is thirsty. It requires irrigation to grow in Kenya. And Kenya is currently in water crisis. but perhaps you'd rather think about or eat a fresh marula fruit well if you're not in sub-saharan africa in the summer good luck to you people say it tastes like a combination of pineapple mango lychee and guava which sounds amazing i would like to try one myself very much but the marula fruit doesn't show up in U.S.

15:29supermarkets. It doesn't refrigerate well, and so it can't be a commodity the way an avocado can. This is another consequence of refrigeration. Yes, the cold chain means that those of us that are connected to it can eat fresh produce all year round, but only those fruits and vegetables that can be refrigerated. So these are just a couple of examples. There are similar stories to be told about all perishable foods all over the globe. But I hope you're starting to see something that should be obvious, but hasn't really been part of the conversation until now, which is that refrigeration has costs as well as benefits.

16:12We implemented mechanical refrigeration in the late 1800s to solve two very specific problems. How to make lager beer in the US in summer, and for real, and how to get meat to people living in the world's first truly big cities. It has solved those problems and been some. In countries with a US-style cold chain, people can now eat meat and tropical fruit in quantities that would have been previously unimaginable even for royalty and at prices that mean that almost anyone can have a burger, a bud, and a banana every single day of the year. This is miraculous, but it has trade-offs. And the biggest trade-off of all is that cooling the artificial cryosphere is melting the natural one.

17:08The chemicals and energy used to refrigerate food already account for between 2.5 and 3 percent of all global emissions. That's just cooling food, not buildings or server farms or any of the other things we keep cool. That's the same as maybe even a little more than global aviation. And like I said, the cold chain is growing fast. Developing countries want a cold chain for good reasons, because it will help them make money exporting crops like avocados, and because it will help them reduce food waste. That's true, but only partially. Refrigeration is really effective at reducing waste between the farm and the market.

17:56Before the U.S. had a cold chain, 30 percent of everything it grew rotted before it made it to market. Today, those losses have shrunk almost to nothing. But guess what? Now Americans throw away 30 percent of everything that makes it to market. Refrigeration moved where the waste takes place. It didn't eliminate it. And as for exports, that's a game you only win by competing on price, which means scale, which means a few large firms owned by multinationals. Meanwhile, you've drained your aquifers and replaced your marula trees with avocado plantations. Reducing food waste and lifting smallholders out of poverty are important goals.

18:44Building a U.S.-style cold chain might not be the best way to achieve them. What's more, if we build a U.S.-style cold chain for everyone alive today, the emissions from refrigeration will multiply by five, at which point they'll be the same size as the entire U.S. emissions. In other words, unimaginably huge. Okay, so that's the doom and gloom part. This is a crisis, but it's also an opportunity because most of that cold chain hasn't been built yet. This is the moment to rethink our relationship with refrigeration. And just like developing countries skipped landlines and checkbooks in favor of cell phones and digital banking, they can do better when it comes to food preservation.

19:36And then we in developing countries can learn from them to remake our own food systems. What might this look like? Well, for one, we can change how we refrigerate. One example, if you disturb the molecules, the atoms in particular types of materials, they will suck in heat energy from their surroundings to reorganize themselves. Bingo, you've created a fridge. Scientists have a super cool, pun intended, prototype. It works by squeezing and releasing a cheap and common form of plastic, and it produces the same amount of cooling for less than half the emissions of an old-school fridge. So changing how we refrigerate can reduce emissions.

20:26It is a solution. It is not the solution. Ultimately, we have to think about our goals. We want our beer cold. But for most food, the real goal is freshness. So what if we could achieve freshness without cold? Good news. Already, you can buy fruit that has been sprayed with an edible fat-based powder that forms a nanoscale coating that keeps produce fresh at room temperature for nearly as long as the fridge keeps it in the cold. So imagine a smallholder farmer in Africa being able to preserve their harvest using a spray bottle rather than a power hungry fridge. There's also a new process in commercial development that uses supercritical carbon dioxide to keep meat good at room temperature for six months plus.

21:22Or if you say, well, refrigeration compressed geography by expanding perishable foods travel time, well, why not speed up travel? Right now, America's largest grocery is delivering unrefrigerated chicken and ice cream by drone in Arkansas, taking refrigerated trucks off the street and refrigerated supermarket shelves out of the equation. Even in the kitchen, people are working to liberate food from the fridge. Many fruits and vegetables actually taste better, have more nutrients, and last longer in slightly warmer, more humid conditions. So why not shrink our fridges and redesign our homes to allow that?

22:10Just to be clear, I am not anti-fridge. I love my fridge. Refrigeration has an important role to play in any future food system. But let's approach it a bit more like we do cars. These days we know we can electrify them, and we can remove them from our city centres, and we can replace them in some situations, replace them all together with bikes and better public transit. And these can be better ways to achieve both our mobility goals and our sustainability and quality of life goals. So let's think like that about preserving freshness, using refrigeration only when it's the right solution, while also redesigning our fridges to make them more sustainable.

22:57And maybe we can save the planet, fix our food system, and make life more delicious. Thank you.

23:11That was Nicola Twilley at TED Countdown Summit in 2025. Cold has become our default solution for keeping our food safe and fresh. We often treat refrigeration like the ultimate safety net. But as food writer Nicola Twilley just showed us, refrigeration goes beyond household appliances. It's a vast global system that shapes what we eat, where it comes from, who benefits, and how much energy it takes to keep it all running. Both of today's talks remind us that safety always comes with trade-offs. Protecting ourselves from pathogens requires vigilance, regulation, and infrastructure. Preserving freshness at scale requires energy, resources, and global coordination.

23:56And sometimes, the very systems designed to keep us safe create new challenges we then have to figure out how to manage. My hope is that listening to these talks leaves you feeling informed and not anxious. Food safety doesn't have to be about fear or perfection. At least that's what I am telling myself. It can be about understanding where risk actually lives, how our bodies work, how our food systems operate, and where small changes truly matter. It can mean being thoughtful without being obsessive, curious instead of complacent, and a little more aware the next time you're standing in front of your fridge deciding what to eat and what to toss.

24:44And that's it for today's episode. Thanks so much for listening. TED Health is a podcast from TED. And I'd love to hear your thoughts about this episode. Send me a message on Instagram at ShoshanaMD. This episode was produced by me, Shoshana Ungerleiter, and Jess Shane. Edited by Alejandra Salazar and fact-checked by Vanessa Garcia-Woodworth. Special thanks to Maria Lages, Farrah Degrange, Daniela Balarezo, Constanza Gallardo, Tansika Sangmarniwang, and Roxanne Highlash.

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