Your phone is disgusting. Here's how to clean it | Lotti Tajouri

0:00Lotti Tajouri: You can wash your hands perfectly, but the very moment you touch your phone, you recontaminate them. Remember, your phone is your third hand, and it is the dirtiest one you have.

0:18TED: You're listening to TED Talks Daily, where we bring you new ideas to spark your curiosity every day. I'm your host, Elise Hu. You wash your hands after using the bathroom, before eating, and when caring for someone who's sick. But what about after holding the object you touch thousands of times a day? For molecular biologist Lati Tajuri, that question became personal after he watched healthcare workers use their smartphones in the operating room during the births of both his children. So he started swabbing phones, and what he found was unsettling.

0:50Lotti Tajouri: In our research at Bond University and Murdoch University, Australia, we swab 26 mobile phones belonging to doctors and nurses, working in pediatric wards and intensive care. On those phones, we identify over 11 ,000 microorganisms, including bacteria and viruses responsible for serious hospital-acquired infections.

1:16TED: In this talk, Lottie takes us from hospital wards to international airports, showing how our phones carry microbes, including drug-resistant ones, everywhere we go, and how they can undo even the most careful hand-washing. But he says the fix doesn't have to be complicated. That's coming up right after a short break.

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3:41TED: And now, our TED Talk of the day.

3:46Lotti Tajouri: In 2014, my beautiful wife, Sandra, and I were expecting our first child. Close to the due date, my wife felt unusual movement, and being first-time parents, we were understandably nervous, so we rushed to the hospital. The medical team identified that the baby had placed herself in a breech position, and in an act of stubborn determination that we would come to know and love in her, she wouldn't be moved.

4:15Lotti Tajouri: Within minutes, an emergency C-section was called. My wife was calm and brave. I felt like someone had just swept my legs out from under me. A few moments later, I entered the surgical theater to hold my wife's hand during the birth of her daughter, geared up in the full suit of protective equipment, from the very sexy bonnet on my head to the shoe bodies on my feet, all in the name of keeping germs out and the surgical theater sterile. I was nervous and wanted my entire focus to be on my wife, but I could not help but be distracted when I noticed healthcare workers using their smartphones in the theater, gloves on in a supposedly sterile environment.

5:03Lotti Tajouri: In my defense, and I couldn't help it, as a molecular biologist, I knew about all the germs that had just hitched a ride on those phones into that room where my wife's body was exposed through her C-section incision and where my newborn daughter, Emily, was taking her first breaths. And trust me, the germ situation is not good. I didn't say anything at the time. I don't know whether it was the absolute joy and overwhelming sense of love you feel at witnessing the birth of your child, or the fear of what my wife might do if I brought my day job work into her emergency section. I just stayed silent.

5:50Lotti Tajouri: And in the following weeks and months, between the nappy changing, the sleep deprivation, and the joy, it dropped out of mind. I assumed that someone else would realize the absurdity of sterilizing every tool in the room and having everyone wear protective gear while allowing people to bring unsterilized smartphones into that same space and touch them with the very gloves used in patient care. Three years later, we were back at the hospital. Our second baby, Matteo, decided to recreate his sister's Renegades move. This time a transverse position. Another C-section operation followed. And once again, I saw healthcare workers weave smartphones into surgical theater.

6:42Lotti Tajouri: That was it for me. It had now put both of my babies and my wife twice at elevated risk. Now it's personal. I decided I needed to act. Step one, no more babies.

7:04Lotti Tajouri: And step two, I will use my research as a molecular biologist to expose smartphones for what they are. A wonderful tool that left unchecked is a biological hazmat situation we all carry around with us every day. I am on a mission to teach the world how to use smartphones safely from a biological hazard perspective and to make all hospitals, healthcare settings, and quite unexpectedly, our biosecurity safer. So let's talk microbiology for a moment. When we say germs, we're using a broad term. It includes bacteria, viruses, fungi, and protozoa, microscopic organisms that exist everywhere. But it's important to say this clearly.

7:53Lotti Tajouri: Not all microbes are bad. In fact, many are essential. They help us digest food, produce vitamins, and even protect us against infections. We wouldn't survive without them. But that's not what we're talking about today. Today, we're talking about the germs that cause disease, especially if you are immunologically incompetent, vulnerable and fragile. The ones that don't belong on surgical gloves, in neonatal wards or on devices that constantly move between hands, faces and environments. And that brings us to mobile phones. Because your phone is effectively your third hand. Around 80 % of common infectious diseases are spread through hand contact.

8:42Lotti Tajouri: And that's why hand washing works. And it's why a contaminated phone quietly undoes it. We touch our phone thousands of times a day, on average, for three and a half to four hours. And unlike our actual hand, this third hand is almost never cleaned. From a microbiological perspective, your phone is an ideal environment for microorganisms. It's a high touch surface, it's constantly recontaminated by your fingers, and over time it accumulates bacteria, viruses, fungi and protozoa. In other words, your phone is less like a personal device and more like a five-star accommodation hotel for microbes.

9:30Lotti Tajouri: Think about why. First, moisture. When you speak on your phone, you spray it with microscopic droplets of saliva. That creates exactly the kind of humid environment many microbes love. Heat. Phones warm up when they're in use, which turns that humid environment into something closer to a heated spa. And third, food. Skin cells, organic debris, and sometimes actual food. If you've ever eaten while scrolling your phone, congratulations, you fed the guest. And then there's the bathroom. Studies show that between 50 and 80 percent of people use their mobile phones in the toilet, which helps explain why we consistently find fecal and gut-associated microorganisms on phones, including E.

10:31Lotti Tajouri: coli, Salmonella, and Enterococcus faecalis. Your phone doesn't just travel with you, it carries living microbes and contaminants from where you've been, to where you are now, and where you're going next. This is unpleasant in everyday life. It means the phone you take into the bathroom is the same one that ends up on your dining table, in your kitchen, and in your children's bedrooms. But in healthcare settings, it becomes genuinely dangerous. In our research at Bond University and Murdoch University Australia, we swab 26 mobile phones belonging to doctors and nurses, working in pediatric wards and intensive care.

11:21Lotti Tajouri: On those phones, we identify over 11 ,000 microorganisms including bacteria and viruses responsible for serious hospital-acquired infections. Among them were organisms like Staphylococcus aureus and Klebschella pneumoniae. both well-known causes of hospital-acquired infections. We also found multi-drug resistant organisms, the so-called superbugs. This is why we describe mobile phones in hospitals as Trojan horses. Because mobile phones negate hand washing. You can wash your hands perfectly, But the very moment you touch your phone, you re-contaminate them. Remember, your phone is your third hand.

12:18Lotti Tajouri: And it is the dirtiest one you have. And once you see mobile phones as Trojan horses in a hospital, hey, another question follows. What happens when those same phones cross borders? In 2023, I swapped 20 mobile phones from international travelers, attending a medical conference in Sydney. People who had just arrived from five different continents. I was primarily looking for bacteria and viruses associated with human disease. What we found instead were plants and animal pathogens. Among the organisms found on those fawns was Pontoiste Wally, a quarantine pest in Australia. It poses serious risk to agriculture and in rare cases has caused severe illness in native Australian parrots.

13:13Lotti Tajouri: Fawns aren't subjected to the same quarantine controls as our luggage, so the microbes hitching a ride simply pass straight through. During COVID-19, we reviewed studies from around the world. In our systematic review, 45 % of mobile phones tested carried the coronavirus. Once again, mobile phones may have acted as trojan horses, quietly undermining even almost extreme hygiene measures. Now, here's the good news. This is not a problem without solution. In fact, it's a very solvable one. At an individual level, the first step is to treat your phone the same way as you treat your hands. If you wash your hands but never clean your phone, you're only doing half the job.

14:08Lotti Tajouri: Gently wiping your phone, the screen, the back, the sides, with appropriate non-abrasive wipes already makes a meaningful difference. And when you clean your phone, clean your hands as well. That way, you're not immediately undoing the effort. But individual behavior isn't enough in high-risk environments. Hospitals, airports, healthcare facilities, cruise ships. In those settings, we can't rely on perfect human behavior. We need systems that make the safe choice the easy choice. That's where rapid, automated, fun sanitization technologies come in. Tools that can disinfect a device in seconds without damaging it and without slowing people down.

15:02Lotti Tajouri: Those kind of systems already exist. What's missing is widespread adoption. In high-risk environments, individual awareness isn't enough. Hospitals, healthcare facilities and airports already understand this, which is why we don't rely on people remembering to wash their hands. We build hand hygiene into the environment. The next step is to do the same for mobile phones. Ultraviolet C or UVC sanitization is highly effective at killing bacteria, viruses and fungi on surfaces, including all the organisms we've been talking about today. Those systems can disinfect a phone in seconds without damaging it.

15:56Lotti Tajouri: The logic is simple. If we expect people to wash their hands, we also need to give them a way to sanitize their third hand. Left hand, right hand, the phone. In practice, that means placing UVC phone sanitization stations in the same locations as hand washing or hand sanitizer stations, making hygiene complete rather than partial. Ultimately, this requires a mindset shift. We need to stop thinking of mobile phones as neutral objects and start recognizing them as what they are, a third hand, one that travels everywhere, one that crosses boundaries, and one that needs to be included in our hygiene protocols.

16:51Lotti Tajouri: We spent decades teaching people the importance of hand hygiene. But if hand washing is instantly undone by contaminated funds, we're wasting effort, resources, and in some parts of the world, even precious water. What this really calls for is a shift in how we think about hygiene, one that reflects modern life and the devices that rarely leave our side. Let's include mobile phones in how we define hygiene, in our homes, in our hospitals, and in the systems designed to protect public health and biosecurity. Because once you see your phone as your third hand, you realize it deserves the same care, attention, and hygiene as the other two.

18:07TED: That was Lati Tajuri at TEDxBrisbane in Australia in 2026. If you are curious about TED's curation, please visit ted.com slash curation guidelines. And that's it for today. TED Talks Daily is a podcast from TED. This episode was produced and edited by our team. Aspen Fitzgerald Dorsey, Oliver Friedman, Lucy Little, Shu Han Hu, Debbie Rolfe, Emma Taubner, Connor Titsworth, Tansika Sungmar Nivang, and Hannah Yu. Additional support from Isabella Aslarona, Daniela Ballarezzo, Valentina Bohanini, Ban Ban Chang, Christopher Faze-Bogan, Cinnamon Horn, Lainey Lott, Matthew Polis, and Yadi Vasquez. Learn more at podcasts.ted.com.

18:56TED: I am Elise Hu. I'll be back tomorrow with a fresh idea for your feed. Thanks for listening.

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