By Fred Miller
U of A System Division of Agriculture
So, you just had to slip out of COVID-19 isolation to pick up a few essentials at the grocery. You observed social distancing, wore a mask and, after you returned home and put your treasures away, you washed your hands and cleaned your kitchen surfaces just to play it safe.
So far so good.
One question — where was your smartphone while you were out there?
Research has shown that SARS-CoV-2, the virus that causes COVID-19, transfers from infected people onto surfaces by touching, coughing or sneezing, said Kristen Gibson, associate professor of food safety and microbiology for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.
From those surfaces, the virus can transfer to any human hands that touch them. Cell phones have surfaces, Gibson said, and she’s especially mindful of touchscreen smartphones.
“Touchscreens are high-touch surfaces, just like doorknobs and elevator buttons,” she said.
The greatest risk, Gibson said, is touchscreens that are tapped and prodded by multiple users, like self-checkout screens at many stores, or the ones you sign with your fingertip after swiping a credit card at the coffee shop drive-thru.
But the phone in your pocket is also at risk of exposure, Gibson said. A person’s hands touch those public surfaces, then transfer whatever they pick up to their phone.
Gibson recommends not using a cell phone while out running errands — especially during the COVID-19 pandemic. Leave it in a pocket or purse until returning home and washing hands. But if that’s not possible, she advises cleaning the phone as soon as you return home.
It’s best, she said, to clean the phone first, using a damp screen-cleaning cloth or a dry microfiber cloth. Then wash your hands. “The other way around, you risk contaminating your washed hands while handling the phone to clean it.”
And remember, cell phones have surfaces on the back and sides, too. Gibson said it’s important to clean every surface.
Research conducted by a University of Arkansas undergraduate honors student under Gibson’s advisement in Dale Bumpers College of Agricultural, Food and Life Sciences showed that a screen cleaning wipe with isopropyl alcohol and a dry microfiber cloth were equally effective at removing bacteria from smartphone surfaces. Research by other institutions has shown similar results removing viruses from different kinds of surfaces, and Gibson believes such results would transfer to cell phone surfaces.
“And if your phone is in a case,” Gibson said, “you can remove it and clean the case with warm, soapy water, or use a disinfectant wipe.”
She added that spray disinfectants may also be useful, but said she would not use one unless the product is recommended for use on electronic devices.
Concerning those multiuser touchscreens, Gibson said she uses her knuckles instead of her fingertips to tap those. She said stylus pens that have rubber tips for use on smartphones and tablets may also be a good idea to avoid touching fingers to public screens.
Gibson said alcohol-based hand sanitizers are a good intermediary step to clean hands while out and about. But she said wash your hands when you return home.
World Health Organization research has shown that sanitizer formulations vary among products. “Tests show they all have some ability to inactivate viruses,” Gibson said, “but some are more effective than others. And things like how long we rub our hands make a difference.”
“There’s a lot of variability in the products, in terms of alcohol content and use of other ingredients,” Gibson said. “We can’t be certain they remove every trace of virus particles.”
“Washing your hands vigorously with soap and water for at least 20 seconds is the only completely reliable method to be sure your hands are sanitized,” she said.
Gibson said much research remains to be done to measure the effectiveness of various cleaning products and methods. Much research has been done for removing viruses from surfaces in clinical settings, but little has been done in this regard for food industry environments or other places, like homes.
“What we don’t know is what cleaning products or protocols are most effective,” she said. “What is the transmission rate from surfaces to hands? These areas require investigation.”
To learn more about Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website: https://aaes.uark.edu. Follow us on Twitter at @ArkAgResearch and Instagram at ArkAgResearch.