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A weekly show where we debunk common misconceptions. This week, Elliott discusses some misconceptions about germs and hygiene.

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Hey I'm Elliot and this is Mental Floss on YouTube. Today I'm going to talk about some misconceptions about cleanliness and germs.


Misconception number one: The Five Second Rule. If you've been to elementary school (I hope you have) I'm sure you've heard this one. Some claim that if you pick up food off the ground within five seconds after it being dropped, its germ free and safe to eat. There has actually been scientific studies on this and they've found that bacteria does make its way onto food immediately after it hits the ground. It is a smaller amount though so as soon as you pick it up, the less bacteria it will have. The surface that it's dropped on does make a difference. There's less bacteria transfer from a carpet than there is a smooth surface. But the germs aren't like "5...4...3...2...1"

Misconception number two: Soap Kills Germs. Soap is actually a surfactant so when you wash your hands, you combine soap with water then surface tension decreases. This allows for the bacteria to be released from your hands then they just go down the drain. 

Misconception number three: Viruses stay alive on hard surfaces for a long time. Its normal to be a little weirded out about touching things like door knobs and railings in public spaces, but the truth is viruses and bacteria do die on hard surfaces. How long they stay alive depends on the specific type. The flu virus only typically survives two to eight hours. And the cold virus lasts longer but its unlikely to get you sick after 24 hours. And the herpes virus dies after four hours. 

Misconception number four: Urine disinfects burns and stings. Urine is not a disinfectant. See. Aren't you glad you watched this episode? In fact, a 2014 study conducted by the Loyola University Heath System found that there is actually bacteria in healthy human bladders. So, not only is your urine not a disinfectant, its not that safe/sterile in general.

Speaking of toilet stuff,
Misconception number five: The toilet seat is very germy. Well its probably not like the cleanest place on earth but you're unlikely to get a disease from it. It is definitely a misconception that you can contract an STD from a toilet seat. According to the 2002 University of Arizona study, there's around 49 germs per sq. in. on the toilet seat. Compare that with the around 21,000 germs per sq. in. they found on peoples desks at work. Still you shouldn't touch the toilet seat with your hand. Plus the flush handle and other surfaces in the bathroom are even dirtier so make sure you wash your hands. Why don't you just wear gloves all the time?

Misconception number 6: Everyone washes their hands. According to a 2013 study from Michigan State University 10% of people do not wash their hands after using a public restroom. Gross! And that's here in a developed country where we have all the right resources. Hand washing can reduce the risk of diarrheal diseases which affects 1.7 billion people around the world each year. A 2003 hand review of hand-washing studies found that if everyone did wash their hands, there would be between .5 mil. - 1.1 mil. fewer deaths from diarrheal diseases annually. That's insane. 

Misconception number 7: Everyone washes their hands correctly. According to the same Michigan University study that I mentioned earlier, 95% of people are not washing their hands long enough to get rid of germs. So let's take this into the bathroom, so I can show you how to wash your hands.

OK, so the first thing you're gonna need is some clean water. It can either be hot or cold; I prefer tepid. Just lather your hands like this. Now once you have your hands nice and lathered, you wanna do this for about 20 seconds. The Center for Disease Control and Prevention says that is about the same as singing Happy Birthday twice, which obviously I'm not gonna do because it's copyrighted actually - a lot of people don't know that, and also I'm a horrible singer. After you're done just rinse it like this, huh, bet you didn't know that, turn off the water, that's important too. Then you dry off your hands. Thank you so much sir.

Misconception number 8: Hand blowers just blow germs around. The microbiology department at the University of Ottawa has conducted studies about this and determined it to be not true. Hand dryers are not blowing germs all over you. Some claim that dust starts to build inside, leading to bacteria buildup, but that has also been debunked.

Other studies show that hand dryers blow bacteria around the room but these have continually been shown to not be harmful, and no outbreak has ever been associated with hand dryers. Unless you're washing your hands like, in the emergency room of your local hospital, dryers are fine. Also the cool ones are like the ones you put your hands in and it's like the blade. You seen those? Oh they're so cool.

Misconception number 9: Dirty people get lice. Unfortunately you can wash your hair every single day but that will not make lice any less attracted to you. All it takes is head-to-head contact with someone who has lice. This happens to 6-12 million kids between the ages of 3 and 12 in the US each year. Thinking I'm gonna start wearing a hair net around. And maybe stop hanging around playgrounds, which I should probably stop doing anyway.

Misconception number 10: Hand sanitizers cause bacterial resistance. Many believe that hand sanitizers create antibiotic resistant bacteria, also known as superbugs. Superbugs are real, and affect around 2 million people a year, but they're probably not due to sanitizer use. The alcohol in hand sanitizer kills the majority of bacteria on your hands, which involves breaking down the protein in the bacteria's contents. That protein breakdown makes resistance unlikely. It's antibiotics that tend to create superbugs. As long as your sanitizer is at least 60% alcohol and does not contain either triclosan or triclocarban, then you're in the clear.

Thank you for watching misconceptions on Mental Floss on YouTube which is made with the help of all of these wonderful, wonderful people. If you have a topic for an upcoming misconceptions episode that you'd like to see, leave it in the comments and we'll check them out. I will see you next time.