By Angela Vertucci

Widen eye and apply conjunctivitis first to your lower lashes…
Apply dermatitis with a sweeping motion that highlights your cheekbones…
Set lips into a relaxed shape and apply the cold sores generously…

If makeup application guidelines read as they do above, few women would be decorating their faces with the usual decoupage of powders and glosses. Many are unaware, however, that when using shared or expired cosmetics they are likely spreading bacterial conditions like dermatitis (little red bumps that look like acne) and conjunctivitis (pinkeye) to their faces.

Although cosmetics contain preservatives that are meant to prevent bacterial growth, the chemicals cease to be effective after a shockingly brief period of time. Because most females are ignorant of this fact, contaminated makeup is often kept in use, instead of thrown out and replaced. Makeup application tools are also a potential breeding ground for bacteria. Bacterial growth on powder brushes and foundation sponges can occur when these tools are shared among friends or used for a prolonged period of time without washing. The use of contaminated eye makeup and eye makeup tools is especially dangerous, and in addition to pinkeye, can result in redness, itchiness, and sties.

In addition to refraining from sharing makeup, girls should follow these safety tips outlined by the U.S. Food and Drug Administration to avoid bacterial contamination:

1. Keep makeup containers closed tight when not in use.
2. Keep makeup out of the sunlight to avoid destroying preservatives.
3. Don’t use eye cosmetics if you have an eye infection such as conjunctivitis and throw away any makeup you were using when you first discovered the infection.
4. Never add any liquid to a product unless the instructions explicitly tell you to do so.
5. Throw away makeup if the color changes or an odor develops, even if it has not been used for the full duration of its shelf life. Improper care of your cosmetics likely lead to the degradation of preservatives before the expiration date.
6. Wash cosmetic application tools like soft-bristle brushes once a week (yes, that frequently) to remove old makeup, dirt, bacteria, oils, and dead skin cells.

Keeping those pesky microbes and other unsettling debris off your makeup application tools is easy. To clean tools like powder brushes, gently wash them with warm water and either antibacterial face wash or shampoo. Then leave the brushes out to dry on a clean towel. Sponges used to apply liquid makeup should be disposed of after just two uses (assuming that you use each side of the sponge only once).

As for the shelf life of common cosmetics, or the time it takes for makeup preservatives to lose their effectiveness, these guidelines have been provided by Allure Magazine:

1. Face Powders and Blush: 2 years
2. Eye Shadow: 3 months
3. Eye Liner: 3 months
4. Foundation: 6 months to 1 year
5. Powder Concealer: 1 year
6. Liquid Concealer: 2 years
7. Lipstick: 1 year
8. Mascara: 2 to 3 months

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