This morning I stopped at a coffee shop that uses an iPad for a cash register. I ordered a muffin, a coffee, and paid with a credit card. The barrista swiped my card and pivoted the iPad to face me, so that I could sign with my finger on the screen. I was about to when I recalled new research out of Northeastern that finds public iPads are among the most germ-infested places you’re likely to put your hands all day.

The research was conducted by Betsy Hirsch and her colleagues in the Department of Pharmacy Practice, and presented last week at IDWeek, an annual infectious disease conference, held this year in San Francisco. According to a recent post on a Northeastern research blog, Duncan and her team analyzed bacteria on the screens of 30 iPads belonging to members of the Northeastern faculty. Half of those 30 iPads were used in hospitals by faculty members with clinical responsibilities, and the other half were used around campus the way anyone might use an iPad. Duncan found that hospital exposure or not, it didn’t matter: both groups of iPads were teeming with bacteria, including multiple drug-resistant strains.

The article noted that Apple is rumored to be experimenting with antibacterial screens for future iPads. In the meantime, beware of public touch screens. For my part, I signed my name at the coffee shop with my knuckle, and hoped for the best.