Women testing make-up and other products at beauty counters are leaving themselves at risk of a number of infections, a study has found.
So-called ‘tester’ pots and jars were found to expose customers to everything from E-coli to conjunctivitis, the eye disease.
Experts warned that women should avoid using the pots, provided so that they can try out make-up before they buy, as far as possible.
American researchers found that all of the make-up they tested contained traces of E-coli, a cause of major food poisoning, which could cause skin infections in beauty consumers.
The study also found traces of the herpes simplex virus, which causes cold sores. Make-up was most likely to be contaminated on Saturdays – the busiest shopping day of the week. Bacteria die off relatively quickly within make-up, because it does not contain enough nutrients for them to continue to grow.
Dr Elizabeth Brooks, a biological sciences professor at Jefferson Medical College in Pennsylvania, who led the study, said: "Wherever you can see E-coli, you should just think 'E-coli equals faeces.' "That means someone went to the bathroom, didn't wash their hands and then stuck their fingers in that moisturiser."
She added: "If you're asking me if I would personally try a public lipstick tester – or if I would let my teenage daughters do that – then the answer is no. "I would ask for the individual tester.”
The researchers spent two years analysing make-up taken from department stores, specialist shops and chemists.
They used sterile swabs to take samples of products, including skin, eye and lip make-up.They then transferred the make-up onto a chemical substance on which cultures can grow. Between 67 and 100 per cent of the products showed at least some level of contamination,The experts recommend trying on make-up during weekdays, when there are generally fewer customers who could have contaminated the tester.
But women should also wash their faces after trying on make-up from a make-up counter, and be extremely careful when trying on eye make-up.