These Studies Will Make You More Aware of Germs Around You


By Barry C. Fox, M.D., University of Wisconsin

We are all exposed to a huge variety of germs every day. In fact, if Google Glass eventually offers microscopic vision, we may walk around with gloves on and never eat in a restaurant again. Microbes are all around us, and the question is, “What do we have to worry about?”

A modern kitchen featuring flat front cabinets and a linear tile backsplash.
In our homes, the kitchen floor, just in front of the sink, has more bacteria than the trash can. (Image: Artazum/Shutterstock)

Your Home Has More Germs Than You Think

Did you know there are at least several billion microorganisms in our homes? Most of them are harmless, but some could be potentially dangerous. Let’s look at a few.

We all suspect that the kitchen is one of the dirtiest places in a home. One surprise is that the kitchen floor, just in front of the sink, has more bacteria than the trash can. And yes, the sponges around the sink own a large burden of bacteria. Even toothbrushes lying around can be contaminated. In fact, the average toothbrush after brushing has over 10 million germs.

Your shoes have been everywhere. One study found as many as nine different pathogenic bacteria or other assorted germs stuck to the bottom of your shoes. You can then transmit them to tile or carpeting all over your home. Well, what about our personal electronic devices? Studies have revealed 16 percent of cellphones have intestinal bacteria on them.

This is a transcript from the video series An Introduction to Infectious Diseases. Watch it now, on Wondrium.

Public Places Are Also Public to Germs

Businesswoman with protective face mask using phone and looking through the window while commuting on a bus.
There are hundreds of bacteria on rental car seats, as well as on train, bus, and taxi seats. (Image: Drazen Zigic/Shutterstock)

Maybe you’re wondering how long germs can survive on surfaces? In general, cold/flu germs from sneezes can live on hard surfaces for up to 48 hours. The swine flu virus has actually been shown to survive in the environment for up to five days.

A study was conducted in 2011 on possible contamination during a cross-country trip in a personal car, on a commuter train, in a taxi, etc. There were hundreds of bacteria on rental car seats, as well as staphylococcus on train and taxi seats. However, most of them were non-pathogenic bacteria.

How Clean are Restaurants?

Going to a restaurant? As you may have guessed, menus carried the most germs in a recent study—185,000, to be exact. This was followed, in second place, by the salt/pepper holder (11,000 germs). 

And what about hotels? One study found that light switches and bathroom floors were all contaminated with intestinal bacteria. Light switches had 216 bacteria per square inch. And the dirtiest site of all was actually the television remote.

Many people don’t think much about germs in the gym, but in fact, gyms are a haven for germs. The most serious germ you can acquire in the gym is Methicillin-Resistant Staphylococcus Aureus, or MRSA. Also, both plantar warts—a virus—and athlete’s foot—a fungus—can be contracted by going barefoot on gym floors and locker rooms.

Learn more about what the next pandemic might be.

We Have to Travel, but Are We Aware of the Risks?

Flying to your destination? There is speculation that contaminated air circulating on airplanes is responsible for spreading germs. However, a revealing new study cites low cabin humidity as the biggest potential culprit. Why is this?

At low humidity levels, mucous membranes in our noses/throats become drier. In a normal environment, viruses/bacteria are trapped and moved on by the cilia, or hair sweepers, to be destroyed by infection-fighting white blood cells. When the membranes are dry, the mucus may become too thick to move easily. Therefore, viruses and bacteria stay in the upper respiratory tract for longer periods of time.

Learn more about emerging and reemerging diseases.

A Safe Distance from Coughs and Sneezes

Image of passengers in an airplane.
Airplanes have high-efficiency air particulate filters, with the ability to filter more than 90 percent of known particulate matter. (Image: Matej Kaatelic/Shutterstock)

Importantly, six to eight feet constitutes a safe distance that bacteria/viruses cannot really be transmitted by aerosolized means of coughing or sneezing. Why? Because most of the bacteria/viruses will fall harmlessly to the ground in that distance. There are however a few germs with exceptions to the six to eight feet rule.

You might be surprised to know that the actual airplane air is as well protected as the inside of a hospital. Airplanes have high-efficiency air particulate filters, or HEPA filters, with the ability to filter more than 90 percent of known particulate matter, including those that may be suspended in the air.

Common Questions about Studies That Will Make You More Aware of Germs Around You

Q: How long can germs live on a surface?

Usually, the germs around you that live on hard surfaces last up to 48 hours. But there are exceptions to these that last much longer, like the Swine flu that can stay in your surroundings for five days.

Q: What illnesses could you contract in a gym?

If you start walking around barefoot on the floors in a gym, there’s a chance of getting athlete’s foot or plantar warts or even both. MRSA is also a serious germ that you could get while in the gym.

Q: Why does low cabin humidity in airplanes increase the chance of getting sick?

When the humidity in the cabin is low, our throats become drier, and this leads to our mucus becoming thicker. Meaning the germs we catch will stay in our throats for longer periods of time.

Keep Reading
Bacteria That Produce Dangerous Toxins
Pathogens: How Do They Affect the Human Body?
Bacteria: Anatomy and Functioning