SALT LAKE CITY -- It is a fact of life -- germs are all around us.

But we wanted to find out what's lurking on items you come in contact with the most. We came up with a "Top 5" list of dirtiest objects and places in everyday life -- and the results will have you reaching for the sanitizer.

#5: Doorknobs and handles

Our countdown kicks off with doorknobs and handles. There's no way to really avoid them -- you've got to get inside the place you're going somehow. Only your hands can get you there.

"If you go into a door that's been opened by tons of people in a public place, it's likely to have more bacteria or viruses on it, especially because somebody with a cold may have just opened the door right before you," said Dr. Shankar Swaminathan, the chief of infectious diseases at the University of Utah Department of Medicine.

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As parents of young children we soon discover our kids don't seem to be at all hesitant to touch, lick, and even eat the nastiest of things.

We wanted to see just how filthy a frequently-used door handle can be, so we headed to the Salt Lake City Public Library -- a place where the door hardly has time to close. We swabbed a few handles and found more than 20 bacteria on each.

The good news about doorknobs and handles -- most are made of metal.

"Things that are not porous -- like metal, particularly brass -- tend not to grow a lot of bacteria," said Swaminathan. "Some metals may actually be anti-bacterial themselves."

So while definitely dirty, doorknobs aren't the best breeding ground for bacteria.

#4: Light switches

When you hear No. 4 on our list, a "light" might go on.

"Light switches," said Rebecca Ward with the Utah State Health Department. "We're always turning on and off the lights."

Mother of three, Desiree Werrett, directed us toward the most frequently-used light switch in her home. With little ones, she keeps a clean and germ-free house. But this is one area she's never considered.

We swabbed her switches and found over 300 bacteria on each of her light switches and lamp.

#3: Money

You know that term "dirty money"? We mean it literally.

"It's kind of a sticky, porous surface and bacteria can live on it," said Swaminathan.

Few people handle more money than bank teller, Terry Marsh.

"My mom had always taught us that money is really dirty," she said. "But I learned how dirty."

By the time some bills get to her, they've changed hands hundreds of times and she can definitely tell.

"Money that's been in the mud will feel different than money that's been passed through sweaty hands," she said. "It can be gross."

But just like their worth, not all bills are equal when it comes to cleanliness.

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Killing every germ is not good for people. It causes allergies, weakened immune systems and superbugs.

"Dollar bills tend to be more handled than hundred-dollar bills obviously, and so they may have more bacteria," Swaminathan said.

So, just how dirty is it? Our tests showed nearly 500 bacteria on each bill we tested.

#2: Keyboard and mouse

"They're terrible as far as the number of bacteria that are likely to be on them," said Swaminathan.

Very few people think to wash their hands before they type an email, and same thing with washing their hands afterwards. So places like a computer lab at the University of Utah are likely to have as many germs as words typed per minute.

Senior Nathan Shumway admitted to be getting over an illness. Many of the students around him in the computer lab were eating as they typed -- potentially exposing themselves to all kinds of germs.

"It does kind of gross me out now that you talk about it," he said.

Just how gross? The keyboard we tested contained around 250 bacteria and tested positive for staph. That means in a day or two, Nathan won't be the only one who is sick.

#1: Kitchens

Believe it or not, the kitchen is the source of most of the germs of your home. In addition, the dirtiest place in the room is probably the place you think is the cleanest -- the sink.

"It's warm, it's moist, it's wet," said Ward. "Bacteria tend to thrive in things like that."

With four kids, pets and homemade meals every day, Andrea Ferguson's sink is working overtime. Her kids help with cleanup, but it's inevitable. Your sink, sponge and scrubber soak in all the things you try to wash away.

"We use it all day long, really," she said. "From when we get up and then we've just got things going on constantly."

We found more than 5,000 bacteria, along with 2,500 coliforms and staph between the sink and scrubber.

But before you zip yourself in a sterile plastic bubble, take a deep breath and remember:

"In-tact skin is a wonderful protection," Swaminathan said. "This is part of daily living and one just has to practice common-sense hygiene."

Something dirty we didn't include on the list: cell phones. Doctors say they're less likely to get you sick because they carry your own personal germs, rather than other people's germs.

Email:jstagg@ksl.com

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