Total germ phobe? Steer clear of your favorite makeup counter. A new study indicates that the products you’re encouraged to test out might actually make you sick.

According to Dr. Elizabeth Brooks, a biological sciences professor at Jefferson Medical College in Philadelphia (and the author of the study), the problem exists at local drug store chains all the way up to the chi-chi department store outposts where one tube of lipstick can set you back a few hundred dollars.

“We went to department stores, specialty stores, drugstores — everywhere,” she explains. Extensive laboratory study found active cultures of staph, strep and even E. coli bacteria on makeup testers. “Wherever you see E. coli, you should just think ‘E. coli equals feces,’ ” Brooks asserts. “That means someone went to the bathroom, didn’t wash their hands and then stuck their fingers in that moisturizer.”

And the worst day of all to try on make-up? Brooks says that tests run on Saturdays indicated that contamination was at 100%.

Word to the wise? Just buy it and return it if you don’t like it. Better to blow some cash then spend the whole day worrying if that scented lotion you rubbed on might be scented by something else entirely…