In this article on Refinery29.com, Philip M. Tierno, Ph.D., professor of microbiology and pathology at New York University School of Medicine, gives us the lowdown on why seemingly new underwear could be tainted:
"No store policy can guarantee that every interested shopper kept her undergarments on in the fitting room, or that you’ve truly got a fresh paper liner to work with. (Or, that there's no menstrual blood, which Dr. Tierno once found while testing underwear for pathogens.)"
The piece goes on to explain how many people may have touched the undies, a slew of scary germs they may be exposed to, and <shudder> how long these germs can live... Up to six months!
So do yourself a favor if you find yourself in a pinch without a fresh pair... Buy Cheeki undies, which are untouched and untried, and breathe a little easier.