Dirty beauty applicators can be a breeding ground for skin irritants like mold and bacteria.

Would you consider eating a slice of moldy bread? Chances are there may be just as many gross microbes present in your favorite beauty products that you diligently put on your skin every day—and the tools you use to apply them. Cosmetics Package Cap Mould

According to a 2019 study published in the Journal of Applied Microbiology, 70-90% of all products tested, including lipsticks and makeup sponges, were contaminated with fungus and bacteria.

"Mold can grow on skincare and makeup items for a variety of reasons. When the product is past its expiration date, when they aren't stored properly and when the applicators are not cleaned regularly and thoroughly, to name a few," says Michael Rubino, air quality expert and author of The Mold Medic.

"Sometimes mold formation could be the result of a wrong product formulation in which case the responsibility lies with the manufacturer rather than the consumer," says Luisa Fanzani, LA-based cosmetic chemist and founder of her eponymous skincare brand. "When this happens the FDA has the authority to force the company to recall the batch that’s contaminated," she notes.

"Unfortunately mold does not present the same way that it does on a loaf of old bread. So you have to use your senses to determine if there’s mold growing in your products," says Roberta Moradfar, advanced aesthetics nurse practitioner and founder of EFFACÈ Aesthetics.

"A visual inspection of the product is the first step, but it’s not the end-all-be-all," says Rubino. "Mold spores are microscopic, so the growth could be occurring below the surface or deep within tools where it's too small to be visible just yet," he explains.

"Sometimes, the color of the mold growth blends in with the color of the product or tool. In cases like this, you can use your nose. Growing mold often releases an earthy, musty smell that indicates there’s something funky going on within the product," says the mold expert.

In addition, pay attention to your health. "Your body has amazing warning systems for when something isn’t quite right, but you’ve got to listen to what it's trying to tell you," says Rubino. "Chronic skin issues that just randomly appear or other health reactions could point to mold exposure from your beauty products," he adds.

Using products that have been contaminated by mold can seriously irritate your skin, causing breakouts, rashes, itching and allergic reactions such as itchy or swollen eyes. "It can also trigger your symptoms, if you have asthma," says Moradfar.

"For example, applying mascara contaminated with bacteria like P. Aeruginosa might cause severe eye infections," says Fanzani.

Meanwhile, "if your skin is already inflamed or the skin barrier has been weakened by the use of aggressive cleansers, pollution and other environmental factors, applying moldy cosmetics on it can lead to even more irritation, redness and allergies, among other skin issues," notes Fanzani.

Frame Plug Mold Here are seven expert-backed tips to prevent mold and bacteria from growing in your beauty arsenal: