If those annoying photos of food that your so-called friends keep clogging your Facebook feed with are any indication, folks are getting increasingly comfortable whipping out their smartphones at the dinner table. This isn't just bad manners; this could be hazardous to your health.
Take out your device at chow time and you may be dialing up a side of bacteria with your rack of lamb. "Mobile phones have become veritable reservoirs of pathogens as they touch faces, ears, lips and hands of different users of different health conditions," a pair of researchers observed in a 2009 study of bacteria removed from personal calling devices. Some of the germs they found are the source of a wide variety of nasty bugs, like the flu and pinkeye. Others could possibly -- albeit unlikely -- even lead to fatal infections [sources: Famurewa and David, van Gilder Cooke].
So, before you take out your mobile gadget to document your next adventure in food porn, take a gander at some of the bacteria and other micro-organisms that you might be bringing to the table.
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The next time that you find yourself bowing down to the porcelain gods, remember that a mobile device may be to blame. University of Arizona microbiologists turned some heads in 2012 when they released a study concluding that smartphones carry more bacteria on average than toilet seats. Some experts say we shouldn't be surprised: Human thighs generally carry less bacteria than our mouths and hands, and even the most dedicated germaphobes tend to clean their johns more often than their gadgets [sources: Hawkes, Coil].
Still, it's hard to get over the ick factor. Coliforms are bacteria often found in animal and human feces, as well as on soil and plants [sources: Washington State Department of Health, Coil]. They're also commonly uncovered on the surfaces of personal cell phones. While smaller amounts of these bacteria aren't likely to make you sick, their presence on your mobile device is a good indicator that other pathogens are lurking.
9: Escherichia Coli
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Like many of the items on this list, Escherichia coli (aka E. coli) just sounds like something that you probably want to avoid. The truth is that not all strains of these bacteria are actually harmful. Some are even beneficial to your digestive tract.
A type of fecal coliform, E. coli strains regularly reside in human intestines, and their presence on a cell phone could be a sign of other contamination. In rare cases, a phone could be infected with a very nasty strand called E. coli O157:H7. This is the version of the pathogen that produces the foodborne outbreak scares that we see in movies and local news broadcasts. While it usually leads to severe cramps, diarrhea and vomiting, an outbreak occasionally can have fatal consequences [sources: Locke, Centers for Disease Control and Prevention].
8: Staphylococcus Aureus
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Staphylococcus aureus is another common type of bacteria whose harmfulness depends on the strain. Some kinds of S. aurea bacteria can cause serious skin infections, commonly referred to as staph infections. Methicillin-resistant Staphylococcus aureus (MRSA), for example, is a rather nasty version of the pathogen that causes painful skin boils and is transferred by skin contact. It's typically spreads in hospitals and other health care settings, a process that can be quickened via dirty cell phones [source: Mayo Clinic].
In a 2009 study, Turkish microbiologists found that more than half (52 percent) of the 200 health care workers' mobile phones that they tested were contaminated by Staphylococcus aureus, and that 38 percent of those phones had been exposed to the methicillin-resistant strands of the bacteria [sources: Ulger et al., Mayo Clinic].
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Anderson Cooper has seen a lot of things during his time on the small screen. The silver-haired news anchor has followed deadly crocodiles into underwater caves, chased hurricanes in New Orleans and dodged bombs in the Middle East. But CNN's leading man was never more shaken than when he learned that his "beloved" BlackBerry tested positive for fecal strep [source: Perricone].
Streptococcus generally comes in two forms, commonly referred to as group A and group B. The first type of the bacteria is the one that many of us encountered as kids in the form of strep throat. It can also cause more serious maladies, like scarlet fever, toxic shock syndrome, cellulitis (infection that causes the skin to swell) and a flesh-eating disease called necrotizing fasciitis. Group B is also something you don't want to tussle with, as it can leave you with pneumonia, as well as a urinary tract, blood or skin infection [source: National Library of Medicine].
6: Coagulase Negative Staphylococci (CoNS)
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Try saying this one five times fast. A species of staphylococcus, Coagulase Negative Staphylococci (CoNS) is antibiotic-resistant and usually resides in human skin and the vaginal tract. While generally less harmful than Staphylococcus aureus, the bacteria are a common cause of bloodstream infections, including those resulting from contact with hospital surfaces and medical devices. CoNS has been found responsible for up to 30 percent of health care-related blood infections [source: CDDEP].
The bacteria are also prowling around smartphones and other devices. In 2011, a group of university researchers from Ghana swabbed the surfaces of mobile phones from 100 randomly selected students. Fifteen percent of those devices tested positive for CoNS [source: Tagoe et al.].
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Mold isn't just the stuff growing on those chimichangas you put in the fridge four weeks ago and haven't gotten around to throwing away. It also showed up on 10 percent of the cell phones tested in the Turkish health care workers' study.
Sure the stuff will make the old ice box smell ripe and it looks less than appealing when covering the wall of a bathroom, but it can also cause health problems. Exposure to mold is likely to affect the respiratory system, resulting in shortness of breath, nasal stuffiness, fever and—in less common cases—lung infection [sources: Ulger et al., CDC].
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In the same way that some of the bacteria on this list can actually be beneficial to digestive health, yeast also serves important functions. Namely, it's used to make pizza and beer. Yes, it is safe to say that the world is a better place with yeast in it. But that doesn't mean you want your phone caked in it.
The same Turkish study mentioned earlier found yeasts on about 1.5 percent of the phones tested [source: Ulger et al.]. Yeast is a fungus that can live almost anywhere on your body. Yeast infections cause immense itching on your skin or vagina and in the case of the vagina, a discharge as well [source: National Library of Medicine]. The good news is that you're unlikely to contract a yeast infection from your mobile device. Unless, that is, you're doing some pretty strange things with your phone.
3: Clostridium Difficile
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Clostridium difficile is a fancy, scientific way of saying "the stuff that causes diarrhea." Patients who are elderly or have been using antibiotics for extended periods of time are especially susceptible to this form of the runs [sources: National Library of Medicine, Murphy]. At least now you know that the toilet seat that you'll be spending the foreseeable future on is probably pretty darn clean.
C. difficile is also known to cause other conditions, like fever, nausea, abdominal pain and loss of appetite. The bacteria often spread in hospitals. An infection is unlikely to occur in healthy people, but cleaning your phone every once in a while is a good idea. Apple advises against using solvents to clean its gadgets, saying just to wipe them with a soft cloth. Other tech experts use a solution of isopropyl alcohol and distilled water, sprayed on a soft cloth for wiping [sources: National Library of Medicine, Murphy].
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No, this isn't a microorganism that cracks bad jokes. It's a pathogen whose toxic strains cause diphtheria, a potentially deadly disease in which toxins coat the infected person's throat and make it difficult to breathe. Diphtheria starts as a cold, before graduating to a fever and chills, and even heart attack [sources: CDC, Murphy].
Fortunately, vaccinations are widely available in developing countries. In the U.S., the disease is largely nonexistent. That means that the corynebacterium found on cell phone swabs taken by University of Oregon researchers in 2014 probably weren't of the toxic variety [sources: CDC, Murphy, Munoz].
1: Pseudomonas Aeruginosa
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This "opportunistic pathogen," as described by one team of microbiologists, works its way into a wide variety of settings. It requires little nutrition and can tolerate a range of settings, from hospital equipment and sinks, to community pools and even your talking device. In a study of 400 cell phones, Nigerian researchers found the bacteria were among the most common lurking on the gadgets [sources: Lister et al., Akinyemi].
What separates Pseudomonas aeruginosa from other items on this list is its amazing ability to resist treatment after infection. The more severe of these infections typically occur in hospitals and particularly among intensive care patients [source: Lister et al.]. That sounds like a good enough reason to make the ICU a cell-phone-free zone.