This article originally appeared in the San Francisco Chronicle’s health section on January 30, 2013.
With flu season in full swing, it’s useful to know which surfaces in public places harbor the most germs – and the answers might surprise you. Many people expect bathrooms to have high germ counts – and they often do – but so do kitchens and water fountains, light switches and remote controls.
Many germs also live on keyboards and phones, which come in close contact with hands, noses and mouths. But, as Charles Gerba, a University of Arizona microbiologist involved in many of the germ studies, points out, most of the germs in these places are your own – so they’re unlikely to make you sick.
Here are the numbers:
The percentage of sink faucet handles in office break rooms that had high levels of contamination, according to a 2012 study by Gerba and the Kimberly-Clark hygiene product company.
The percentage of break room microwave door handles that had high levels of contamination. Refrigerator door handles, water fountain buttons and vending machine buttons were also big germ culprits.
The average number of colony-forming units of bacteria found per centimeter squared on hotel room light switches in a separate study from the University of Houston. The study was small, involving only nine hotel rooms across three states, but light switches were among the most contaminated hotel surfaces, along with TV remotes, bathroom sinks and floors.
The colony-forming units of bacteria found on the sponges housekeeping staff use to clean hotel rooms. Mops, sponges and cleaning gloves had higher bacteria counts than any hotel surface, increasing the likelihood that germs can be spread between rooms.