When Dana Chianese noticed a musty smell coming from her son's Sophie the Giraffe teether, she decided to cut it open. Inside the popular baby toy, she discovered a "science experiment": The latex figurine was lined with "smelly, ugly" mold, Chianese, a pediatric dentist, recently told GoodHousekeeping.com—even though she had always cleaned it according to the instructions (with hot, soapy water and a damp sponge) and never submerged it.

She's not the only mom to make that disconcerting discovery: Last February an Amazon customer posted a photo of the inside of her child’s Sophie, also covered in mold. Yikes.

But allergist Janna Tuck, MD, a spokesperson for the American College of Allergy, Asthma, and Immunology, isn't surprised by these reports: "Teething infants drool a lot and I think it would be impossible to keep the inside of a well-loved Sophie completely dry," she told Health via email. “Mold can grow on almost any surface if there is enough moisture."

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The good news is that a moldy chew toy isn't as risky as it sounds: "While disgusting, the amount of mold in a toy would not likely cause significant harm unless the child has an immune deficiency or a mold allergy," says Dr. Tuck, who runs a private practice in Cape Girardeau, Missouri.

The not-so-good news? Toys aren't the only unexpected objects that can harbor fungi (mold is a type of fungus). Mold may be lurking in your washing machine, dishwasher, blender, or refrigerator, says Dr. Tuck. It can be found in the soil of potted plants, on ceiling fans, and in window AC units. In your bathroom, it might be growing in your toilet, sink—even in the bristles of your toothbrush, or inside your electric toothbrush.

When mold grows in hidden places, it can cause real problems for people who are allergic. "They can suffer with allergic rhinitis symptoms," Dr. Tuck says, such as itchy eyes, congestion, runny nose, and sneezing. Or the mold may worsen their asthma symptoms.

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So what can you do to keep your home fungi-free?

To reduce the growth of mold in your washing machine and dishwasher, you can regularly run the "clean cycle" with diluted bleach. Most manufacturers recommend monthly cleanings, or whenever the machine begins to smell musty, says Dr. Tuck. Check the owner's manuals to see exactly how much to dilute the bleach before using. "Vinegar is a very good substitute," she adds. "I personally run vinegar in my dishwasher."

When you're taking a bath or shower, always use the vent in the bathroom. Also be sure to turn on the vent in the kitchen whenever you're cooking and washing dishes, says Dr. Tuck, "to reduce spikes in ambient humidity."

After you use any food prep vessel (like your blender), clean it promptly and dry it fully, so no moisture is left sitting inside. And replace your toothbrush every three months, says Dr. Tuck.

Another place mold likes to hide: "cold" spots in your home. If you have rooms or closets that seem cooler than the rest of the house, leave the doors open to improve air circulation, and help prevent condensation. Leaving the fan in your central heating/cooling unit on at all times can help as well. "Mold needs water to grow. Anything you can do in your home to reduce humidity, condensation, or pooling of water goes a long way in reducing mold growth," says Dr. Tuck.