Most beauty junkies know that sharing makeup isn’t the greatest idea–gloss, mascara, and powder can carry all sorts of unsavory germs (think cold sores and pink eye). If sharing makeup with your BFF could potentially lead to infections, imagine the risk you take every time you sample a makeup tester shared by thousands of strangers! According to the LA Times, if you don’t practice safe hygiene–or insist that the salespeople practice safe hygiene–you could expose yourself to life-threatening bacteria. Results from a Rowan University study showed that an overwhelming number of department store, specialty store, and drugstore makeup testers carry staph, strep, and E. coli bacteria–and when the makeup was tested on Saturdays (the busiest retail day of the week), the percentage of tainted makeup was 100%. “Wherever you see E. coli, you should just think ‘E. coli equals feces,'” Dr. Elizabeth Brooks, the scientist who conducted the survey, told the LA Times. “That means someone went to the bathroom, didn’t wash their hands, and then stuck their fingers in that moisturizer.” Okay, yuck. The good news is, there are ways to enjoy beauty-shopping while also protecting yourself. Want to sample a lotion? Skip jars that you need to stick your fingers into; try a lotion you can squeeze on, instead. Also, always use disposable applicators to try on makeup, never apply straight from the gloss or lipstick tube (scrape off the surface layer of the lipstick before sampling), and avoid communal makeup brushes, altogether. And don’t be afraid to ask the salesperson for disposable brushes or pads if you don’t see any. “[Most stores] have all of that behind the counter…just not for the general public to pick up at their leisure,” Dr. Brooks told the LA Times. She adds, “Even doing all this research, though, I’m not afraid to send my daughters to the mall. I just want women to enjoy makeup but be careful.” Read More: