A survey by the UK College of Optometrists reveals the 92 percent of women are putting their health and appearance at risk by using old makeup.

It’s not generally known that makeup has a sell-by date in most advanced countries. For example :

* Mascara has an expiry date of 3–6 months.
* Liquid and cream foundations, concealer, cleanser, moisturiser, 6–8 months.
* Pressed, loose and compressed powders, eye shadow, blusher, lip gloss, lipstick, toner, 1 year.
* Eye and lip liner, 18 months.

The problem is that these products can be a “hot house” for bacteria which can cause infections when the makeup is applied. The bacteria builds up over time until it becomes dangerous to use. Mascara is a particular problem because the stick used to apply it can scratch the soft tissue surrounding the eye.

The worst offenders, says the study, are women in their 30s and early 40s.

Dr Susan Blakeney, optometric adviser to the college, said, “Mascara can be a breeding ground for bacteria, so it’s not surprising we’ve found nearly half of women suffer from itchy, watery and red eyes when they are holding onto their eye makeup for so long and sharing it among their friends.”

Although the FDA states that there is no absolute date when cosmetics should be discarded, there are some safety rules you should observe to keep your makeup free of contaminants and bacteria.

* Keep makeup containers tightly closed except when in use.

* Keep makeup out of sunlight; light can degrade preservatives.

* Don’t use eye cosmetics if you have an eye infection, such as conjunctivitis, and throw away all products you were using when you first discovered the infection.

* Never add any liquid to bring the product back to its original consistency. Adding water or, even worse, saliva could introduce bacteria that could easily grow out of control.

* Never share.

* Throw makeup away if the color changes or an odor develops. Preservatives can degrade over time and may no longer be able to fight bacteria.

Although the dangers of your own makeup becoming seriously contaminated are slight if they are quality products manufactured with proper preservatives, the same does not hold true for shared products.

Never share cosmetics, not even with a family member or a best friend due to the risk of contamination. And that risk goes up dramatically with shared-use products such as makeup testers in stores and at makeup counters. At home, your makeup usually has the whole day to cope with contaminants before it is used again. But makeup testers in stores are used much more often. According to the FDA, the preservatives in the products cannot handle the challenge of constant use.

The same holds true for those free makeovers at makeup counters. The products used to create that impressive new you may have been used on dozens of other customers before you.

Recent tests done on shared makeup testers by several independent news shows, such as the Today show, found dangerous bacterial contamination, including staph. If you want to test makeup shades, insist on new, individual applicators. Better still, test the makeup on your hand or the inside of your forearm. Never try on makeup from a tester using a shared applicator wand or brush.

Most makeup experts will tell you to replace your mascara every three months and we are similarly cautioned about most makeup products. But according to the FDA, most of your makeup will remain uncontaminated by bacteria even if it is older than three months. In a typically related scenario, a woman putting on mascara while driving, scratches her eyeball with a contaminated wand and infection ensues. The last report of an injury like that to the FDA was in 1989.

The reason? Preservatives.

Cosmetic companies use sometimes 5 or 6 preservatives in a product and the preservatives are very efficient at keeping the bacteria at bay. Contaminated makeup is usually the result of misuse of the product or inadequate preservatives. “Cosmetics are not expected to be totally free of microorganisms when first used or to remain free during consumer use,” according to a 1989 FDA report.

Serious contamination can occur, but it’s rare. Consumers need to be aware and use good hygiene - clean hands, clean face.

Oh, and that warning about not trying to put on mascara while you drive? That’s just common sense.

* The Federal Food, Drug, and Cosmetic Act defines cosmetics as “articles other than soap which are applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance.”

Tomorrow: The risk of contamination in makeup testers