According to the Society for General Microbiology, some bacteria divide every 20 minutes at the right temperatures and with the right nutrients.

A 2016 study of the most contaminated objects in the home also found over 340 different bacteria on 30 different objects.

Not all bacteria are harmful — your body contains plenty of bacteria that don’t make you sick. But some can be found throughout your home and make you sick, including:

  • Staphylococcus aureus, or staph
  • yeast and mold
  • Salmonella
  • Escherichia coli, or E. coli
  • fecal matter

The SARS-CoV-2 virus, the new coronavirus known for causing the COVID-19 pandemic, can also be found on many of the same surfaces. Symptoms of COVID-19 include shortness of breath, coughing, and fever.

It can spread quickly because it lives for hours or days on certain surfaces.

A March 2020 study looked at how long the new coronavirus could live on the following environments and surfaces:

  • in the air: up to 3 hours
  • plastic and stainless steel: up to 72 hours
  • cardboard: up to 24 hours
  • copper: up to 4 hours

Read on to learn about the nine dirtiest spots in your home, how you can keep them clean, and how to protect yourself from the bacteria and viruses that can make you sick.

Bacteria and viruses can spread from person to person and from person to surface.

The 2016 study mentioned earlier about contaminated objects also suggested that several factors influence bacteria and virus life, including:

  • surface type, such as solid surfaces like counters or textured surfaces like furniture or clothes
  • living habits, such as regularly washing clothes or disinfecting surfaces
  • lifestyle practices, such as washing your hands or bathing regularly
  • cleaning procedures, such as using bleach and alcohol versus regular cleaning supplies

Different areas of your home have different levels of risk when it comes to exposing you to bacteria and viruses.

The National Sanitation Foundation (NSF) found that areas where food is stored or prepared had more bacteria and fecal contamination than other places in the home.

More than 75 percent of dish sponges and rags had Salmonella, E. coli, and fecal matter compared to 9 percent on bathroom faucet handles.

Other kitchen items that need frequent cleaning include:

  • cutting boards
  • coffee maker
  • refrigerator, especially areas in contact with uncooked and unwashed food
  • kitchen sink and countertops

Here are some tips for keeping these spots clean:

  • Use disinfectant wipes on the faucet, refrigerator surfaces, and countertops.
  • Heat damp sponges in the microwave for a minute to kill bacteria.
  • Soak sponges in a quart of warm water with half a teaspoon of concentrated bleach.
  • Change dish towels a few times a week.
  • Wash your hands before and after touching or handling food.

Using bleach and rubbing alcohol or disinfectant wipes with over 60 percent ethanol or 70 percent isopropanol is especially effective against SARS-CoV-2 on these surfaces in the kitchen, too.

Don’t forget to wash your hands for at least 20 seconds before and after you touch raw meat or unprepared food.

Countertops, handles, and light switches are a few less-than-obvious places for germs.

While many people assume that the bathroom doorknob would be the dirtiest, the NSF found other spots that ranked higher with bacteria, including:

  • bathroom light switches
  • refrigerator handles
  • stove knobs
  • microwave handles

You can clean these spots once a week with disinfecting wipes. This will also get rid of any SARS-CoV-2 that may be lingering on plastic or steel surfaces like these.

It’s ideal to use a new wipe for every spot instead of reusing the same one.

The nooks, crannies, and bristles of makeup applicators are prime real estate for germs, especially if you carry your makeup bag outside the house.

Germs that live on your makeup applicators can cause skin and eye infections.

The new coronavirus can also get on makeup applicators from your hands and make its way into your nose, mouth, and eyes. This can allow the virus to get into your respiratory tract and cause the COVID-19 respiratory disease.

You may need to change how you store your makeup. Products should ideally be kept in a clean, dry space at room temperature.

To keep makeup brushes clean, you can wash them once a week with regular soap and water, or also use an alcohol spray on the brushes.

It’s recommended to wash makeup applicators at least once a day or before and after each use to prevent the spread of the coronavirus.

Many doctors recommend replacing cosmetics every 6 months and throwing out eye makeup if you’ve had an eye infection or a SARS-CoV-2 infection.

It’s no surprise that the place you scrub dirt and grime off of your body holds bacteria.

Due to the moisture from a hot shower, the bathroom is also a perfect place for germ growth. Spots you should pay special attention to include:

  • shower tub
  • drains
  • faucets
  • floor area around the toilet
  • bath towels
  • toothbrushes

You can wipe surfaces and handles down with disinfectant on a daily basis and do a thorough cleaning once a week.

An old toothbrush may come in handy for cleaning small spaces like around drains and faucets. You should also replace bathroom towels once a week and toothbrushes every 3 to 4 months.

The new coronavirus is less likely to live in your shower, sink, or drains because soap and water are able to wash it away.

But you should still disinfect all surfaces in your bathroom, especially if someone in your home has a SARS-CoV-2 infection or recovered from it.

Wet laundry left in a machine, even for a short amount of time, can cause germs to flourish.

Transfer clean clothes to the dryer immediately after each wash. If clothes sit in the washer for more than 30 minutes, you may want to run a second cycle.

If using a laundry mat or a shared laundry facility, clean the washer drum with a disinfecting wipe.

Be sure to wipe down any surfaces, especially public ones, before folding clean clothes.

Warm or hot water is also more effective in killing both bacteria and viruses like the new coronavirus than cold water. Use hot water whenever possible to wash clothes you’ve worn in public.

Remote controls, computer keyboards, phones, and tablets are often shared by multiple family members and house guests.

In 22 households, the NSF found yeast and mold on the computer keyboard, remote control, and video game controller as well as staph on the last two items.

Surfaces also contribute to bacteria growth and diversity.

For example, a carpet can hold up to eight times its weight in dirt and dust and may be dirtier than a city street.

And as discussed earlier, the new coronavirus can live on plastic remotes and keyboards for as long as 3 days.

Use disinfectant wipes or plain water and soap to clean your items, especially if they’ve come in contact with dirty surfaces like tables or counters.

And wash your hands before touching any household objects if you’ve been out in public or come into contact with someone who has.

Pets can also bring germs and bacteria in your home, especially if they go outside.

According to a study conducted by the NSF, pet bowls placed fourth in spots with the most germs in a home. Pet toys also carried staph, yeast, and mold.

Pets and their bowls, toys, and beds can all carry the new coronavirus, too. Pets aren’t typically affected by COVID-19, but they can carry and transfer the virus to you through your hands or face.

You can prevent your pets from bringing in dirt by washing or wiping their paws before letting them in.

Here are some other tips:

  • Wash pet bowls daily with warm, soapy water.
  • Soak toys and bowls in bleach once a week.
  • Clean hard toys regularly with hot, soapy water.
  • Wash soft toys monthly.

You can bring in bacteria and viruses from the outside to your house each day through your shoes, gym bag, and even headphones.

Of the 22 homes surveyed, the NSF found fecal contamination, yeast, and mold present on:

  • cell phones
  • keys
  • wallet and money
  • lunch boxes
  • the bottom of purses

The new coronavirus can also live on the surfaces for up to 3 days since most of these objects are made of plastic or metal.

Most disinfecting wipes are effective against bacteria and viruses, including the new coronavirus, on electronics. But if you want to be extra safe, you can find electronic-specific cleaning supplies at stores.

One way of keeping bacteria and viruses from spreading is keeping things clean. Use some of these common household items:

  • soap and water
  • bleach and water
  • disinfecting wipes with at least 60 percent ethanol or 70 percent isopropanol
  • hand sanitizers with at least 60 percent ethanol

Here are other good habits to help stop the spread of bacteria and viruses, including the new coronavirus:

  • Take off your shoes before walking through the house.
  • Wash your hands for 20 to 30 seconds after using the bathroom and before and after touching raw food.
  • Wear a cotton or linen mask to cover your face in public to prevent the spread of airborne viruses like the new coronavirus.
  • Wash clothes that you’ve worn in public regularly in warm water (if possible).
  • Stay at least 6 feet away from other people in public (physical or social distancing), especially if they have a confirmed case of COVID-19.
  • Cough or sneeze into a tissue or your elbow instead of your hand.
  • Don’t touch your face with your bare hands.
  • Try to limit going outdoors by working from home or socializing with friends and family through video chat.