In-store cosmetic testers help shoppers decide what looks good on them, but a Marketplace investigation reveals the samples themselves don't always look so pretty under a microscope.

Producers went undercover at a dozen makeup stores in the Greater Toronto Area and swabbed 60 eyeshadow, mascara, lip gloss, cream blush and lipstick testers available to shoppers, and sent them to a microbiology lab for a closer look.

The lab found 40 per cent of the samples had Staphylococcus aureus bacteria, and 28 per cent were growing mould.

Marketplace put samples from in-store cosmetic testers under the microscope. (CBC)

The testers were on display in Shoppers Drug Mart, Sephora, The Body Shop and MAC Cosmetics. Each location had alcohol available to clean lipsticks and tissues to wipe down powders, but many former employees told our producers they only clean makeup when a customer asks them for help.

Keith Warriner, the microbiologist at the University of Guelph who tested the samples, says sharing makeup is risky because eyes and lips, and skin if it's broken, are sensitive areas.

"I always liken it to a toothbrush … if you don't share a toothbrush, why would you go in there and put the makeup on when ... God knows how many people have been there before you?"

He says Staphylococcus aureus is common in humans — up to 40 per cent of us carry it on our skin. But he says your body is used to the strains you are exposed to every day; not the strains of a stranger. This means a makeup shopper with no signs of eye infection can end up giving the next person a stye or pink eye.

"We're used to our own micro flora, but other people's, that's when things start going wrong," he says. "If I had a lipstick and I put it on every day, I'd probably be good … but if I started sharing it, they're introducing new strains which my body's not adjusted to."

Keith Warriner, the microbiologist at the University of Guelph who tested the samples, says if you are going to try on makeup testers, it’s better to apply it on intact skin like on your arm or hand rather than on eyelids and lips, near mucous membrane. (CBC)

Warriner says staph can lead to various skin and eye infections, from pink eye and styes to pimples and boils, while mould more commonly causes allergic reactions that can result in red, itchy eyes.

The International Organization for Standardization does not permit any presence of Staphylococcus aureus on makeup for sale, and Warriner says if it's too unsafe to buy, it's unsafe to try.

After visiting three locations of each of the cosmetic retailers, Marketplace sent 15 samples from each store for testing. Many samples had colonies of staph, mould and yeast.

Sephora: eight staph, five mould and yeast

Shoppers Drug Mart: six staph, four mould and yeast

MAC: three staph, four mould and yeast

The Body Shop: seven staph, four mould and yeast

"I was really surprised by how much contamination was out there ... it's more worrying than I thought," Warriner says. "If they do sanitize these, it's not so effective is it?"

'I didn't clean a tester once'

Marketplace talked to more than 30 current and former employees who have worked at cosmetic retailers. The sanitation protocol for staffers seems to vary significantly depending on the brand and store location. Many said even at stores where staff are trained to sanitize makeup, in practice, they only sanitize a sample if a customer asks to try it on.

"You can't really watch [customers] the whole time," says Vanessa Baudner, a freelance makeup artist who used to work at a Sephora location in Toronto. "You try to clean your brushes or try to clean or sanitize whatever products they're using at the time; it's just really hard to keep on it."

Baudner also worked at a MAC Cosmetics location where she says there was more focus on sanitizing. She says some MAC locations have a second set of testers tucked away that can only be accessed by trained employees who can put the sample on a wand or cotton pad for the customer.

"Definitely approach an artist. Don't take anything off the shelf and try to do it [yourself]," she says.

Brianne Cail worked at a Shoppers Drug Mart Beauty Boutique in Toronto for five months, but says she received no training in sanitizing makeup or applicators.

"I didn't clean a tester once," she says. "There was one time I cleaned makeup brushes after we had a gala but that was at the end of the day. It's not in between customers, for example."

Staphylococcus aureus was found on 40 per cent of the makeup testers that Marketplace producers swabbed. (CBC)

Baudner and Cail both say the makeup samples they had out for customers were often expired, and could be three or four years old.

"Pulling testers is expensive," Baudner says. She says stores won't replace a tester if it still looks new.

"Think about how long it takes you to go through a blush [at home]," she says. "Think about a blush just being there and not being used very much … you don't know how long it's been there."

Alcohol doesn't kill all the bacteria

Microbiologist Keith Warriner says there are misconceptions about the spread of these bacteria and moulds.

When Marketplace asked employees working at the stores if spraying a makeup tester with alcohol would kill all the bacteria, they always said yes.

Marketplace asks cosmetic retailer employees how often their makeup testers are sanitized. 0:45

But when Warriner contaminated a new lipstick with Staphylococcus aureus and later sprayed it with alcohol, he found that it reduced the bacteria by 92 per cent. In Canada, a sanitizer is required to kill 99.9 per cent of bacteria to be considered a "disinfectant."

"It only reduces the risk, it definitely doesn't eliminate," Warriner says.

Trier beware

The four cosmetic retailers told Marketplace they have makeup sanitizing policies in place, and that customers should consult a staff member before trying on a product because they're trained to clean samples.

Cosmetics are consistently among Heath Canada's top 5 product types that injure Canadians based on the number of reports received from consumers. Injuries can range from allergic reactions and irritations to chemical burns and hives.

Health Canada told Marketplace that consumers should not share cosmetics because "repeated use by multiple consumers would always result in a higher likelihood of microbial growth and contamination in cosmetic testers."

Warriner says if you are going to use makeup testers, it's better to apply it on intact skin like on your arm or hand rather than on eyelids and lips, near mucous membrane.

If you must try before you buy, Cail and Baudner both recommend speaking with an employee to make sure the sample is sanitized as best it can be, and never try mascara because it's the most prone to double-dipping.

"I don't share mascara with anybody in my personal life," Cail says. "I definitely don't want to share it with all of Toronto."