Here's a great article from Paula Begoun about E. Coli and other various, icky microbials in tester makeup.
I worked at several cosmetic counters and it used to GROSS ME OUT me how people would just come up to my counter and put tester mascara right on their eyes.
Just read this little gem of tester hygeine etiquette and never put any tester product near your eyes or mouth, dumbass.. .and I just probably saved your life if you do.
"Lots of women love going to a cosmetic counter, salon, spa, or their local Sephora store to play with the skin-care and makeup products on display there (I know I do!). It is almost impossible to pass through the cosmetic section of a department store without something catching your eye. The irresistibly arrayed and easily accessible tester units beckon you to try on a lipstick, foundation, concealer, eye shadow, or moisturizer directly on your face. But you might want to think twice before doing that again because it may be riskier than you think.
Despite the fun you can have at the cosmetic counter, in reality these tester units are almost always rife with bacteria, mold, or fungus (or all three), and that isn’t funny. There hasn’t been a lot of research on the issue, but the little that exists has shown the pretty lip gloss or moisturizer you’ve just tried on is probably contaminated with microbes which can include staphylococcus and even E. coli.
When you think about it, this really isn’t all that surprising. That lipstick you’ve just tried on could have easily been already used by hundreds of other women with unknown hygiene or health (think herpes or pink eye). While preservatives in cosmetics do a great job of reducing the risk of contamination, they only can do so much and they get less effective with time and exposure to numerous microbes from people. Plus, a product’s preservative stability isn’t tested for use by hundreds of users.
In your daily life you would not willingly share your own makeup and skin care with countless women you don’t know, but that is exactly what you are doing when you try on a cosmetic that’s open and available on the counter. It becomes even more problematic on a busy day as a tester is used repeatedly in a short period of time. When this occurs, the preservative system doesn’t have enough time to kill off the contaminants, and that leaves you vulnerable to picking up something you don’t want.
Thankfully, at some cosmetic counters there are salespeople and makeup artists who try very hard to be as sanitary as possible when helping women test products. But given how busy a cosmetic counter can become or if no salespeople are present (which happens quite a bit), or the person behind the counter isn’t well trained, sanitation efforts go right out the door.
While we know there are microbes running amok at the cosmetic counter, the real issue is what are the risks to you? Unfortunately no one knows. Theoretically, if someone with herpes just tried on that lipstick or lip gloss it could get transferred to you, same for getting pink eye from an eye liner pencil or mascara, but there just isn’t any data to reference one way or the other. Theory isn’t fact and there is no evidence anywhere that women are getting any sort of disease from cosmetic tester displays, but they’re not bastions of hygiene, either.
Should you play it safe and avoid the cosmetic counter altogether? Personally I’m not going to give up playing at the cosmetic counter, but there are ways you can still enjoy the experience while playing it as safe as possible:
Eye shadows, pressed powders, loose powders, and powder blushes have the least risk of containing microbes because they contain ingredients bacteria, fungus, and molds don’t like, so they are probably the safest for you to play with. It can be helpful to scrape off some eye shadow (you want to be the most cautious with your eyes) on to Kleenex and then apply it, but check with the salesperson first before you damage a company’s testers.
Lipsticks and lip glosses are problematic to trust, but for lipstick you can roll up the tube and take some color from the bottom. You can also ask the salesperson if they have alcohol spray so you can spray the top of the lipstick or the applicator for the lip gloss before you try it on. Be sure to allow several seconds for the alcohol to disinfect before applying the product to your lips.
Mascaras should never be tested at a cosmetic counter. The application and applicator makes it the riskiest item on the display unit. What about cosmetic counters that offer disposable, single-use brush applicators? They’re a nice touch, but you don’t know if the person before you double-dipped or, for whatever reason, didn’t have hygiene at the front of her mind.
Eye pencils are best tried on your hand, not your eyes. This especially applies to liquid eyeliners, which are almost always water-based. Used on multiple people, liquid eyeliners serve as a fertile breeding ground for bacteria.
Foundations should be tested on the side of the face away from the eyes and mouth to be the safest, but using a clean or disposable sponge is best of all so everyone keeps their fingers out of the product.
For concealer or any product in a tube, squeeze out a little amount on a Kleenex and discard. The contents at the top are the most likely to be contaminated. Next, squeeze out a bit more on a Kleenex and use that to test.
Skin-care products are best tested on your hands to judge the texture (you can’t tell efficacy with one application anyway so there is no benefit of putting it on your face or eye area), or ask the salesperson for a sample if available.
Brushes should be sprayed with alcohol before you use them. Wait for the brushes to dry before using them.
It would be ideal (though given the pervasiveness of jar packaging, not realistic) to test products whose containers kept fingers out of contact with the contents. Products packaged in airless containers or with pump or dropper applicators are safer than those housed in open-mouth jars.
Tester units at salons and spas which have far less traffic than department stores are a safer bet as well (though of course there are less brands and options to try on—but if you are just trying to judge color these can work great)."