Your phone is covered in bacteria, a new study shows. Find out what you're doing with it that's so dirty


You can't live without it, but have you ever thought about how dirty that device you put up to your face really is? Students at the University of Surrey took on the challenge: They imprinted their phones onto "bacterial growth mediums" in Petri dishes and, after three days, looked at what had grown. The results were pretty disgusting: while many different germs appeared on the phones, one common germ was Staphylococcus aureus-the bacteria that can contribute to food poisoning and even turn into a Staph infection. Not totally surprising, considering the average cell phone carries 18 times more potentially harmful germs than a flush handle in a men's toilet, according to tests carried out by British magazine Which? That includes not just Staphylococcus aureus, but also fecal matter and E.coli.

How, exactly, did all those germs get on the phones to start with? Mostly because of what else you've touched: More than 80 percent of the bacteria on our fingers is also found on our screens, a study from the University of Oregon says. That means the germs from the dirty places you touch end up on a screen that then touches your face, your counters, and your friends' hands. Gross! Check out the four worst culprits for where this bacteria comes from. (Then check out Confessions of a Germaphobe: Will These Weird Habits Protect Me (or You) From Germs?)

Digging for Gold


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Before it becomes a Staph infection, Staphylococcus aureusis is actually a pretty harmless bacteria that hangs out in your nasal passage. So how does it end up on your phone? "A furtive pick of the nose and a quick text later, and you end up with this pathogen on your smartphone," said Simon Park, Ph.D. professor of the University of Surrey class that did the experiment. And Staph bacteria can easily spread from contaminated surfaces, so microbes on your smartphone mean germs everywhere you place it.

Tweeting on the Toilet


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Sometimes, we may be a little too addicted to our phones: 40 percent of people admit to using social media in the bathroom, according to market research company Nielsen. Maybe you're just putting your down time to good use, but consider this: A 2011 British study found that one in six cell phones is contaminated with fecal matter. To top it off, the splash radius-and spray zone for all the bacteria in the swirling toilet water-of a flush can shoot as far as 6 feet away, according to the Harvard School of Public Health. (See also: 5 Bathroom Mistakes You Don't Know You're Making.)

Cooking with Technology


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Online recipes have revolutionized the idea of cookbooks, but you're not just bringing your phone into the kitchen-you're bringing it into one of the most bacteria-infested rooms in your house. To start, your moist sink is a breeding ground for bugs. And when you wipe your hands? 89 percent of kitchen towels have coliform bacteria (the germ used to measure water's contamination level), and 25 percent are ripe with E. coli, according to a study from the University of Arizona. (Check out 7 Things You're Not Washing (But Should Be).) That's not even getting into the bacteria from handling dirty vegetables or raw meat. Wondering what a dirty kitchen has to do with your phone? Every time your phone screen locks or you have to scroll through the recipe, all the bacteria that's accumulated on your hands is being transferred to the device you now hold up to your face.

Texting at the Gym


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We all know gyms are teeming with germs, but it all doesn't wash off with a shower. On the treadmill, you're sweatily touching your screen for the next song, and at the weight racks, after grabbing a dumbbell that countless people before you have touched, you're texting. Don't think there's that much danger? Germs can live on hard surfaces at the gym for 72 hours-even after being sanitized twice a day, reports a study from the University of California Irvine. (Check out 4 Gross Things You Shouldn't Do with Your Gym Bag.)