If your microwave smells like mildew, it's a surefire sign of mold growth. You may also notice the physical signs of mold, such as velvety or fuzzy patches of green or black. Under the right conditions, mold can grow almost anywhere, including the inside of a microwave.
Conditions for Growth
Mold cannot grow inside of a clean, dry microwave. Like all living organisms, mold spores require a source of food. Food particles left behind after microwaving can provide sufficient sustenance for mold in the oven, and so can layers of dirt in a microwave that has not been cleaned in some time. In addition to nutrients, mold needs moisture to grow. If moisture is collecting in a dirty microwave, it can develop a mold problem.
Not the Ideal Environment
Even in a dirty microwave, mold will have a very difficult time growing under most circumstances. First of all, mold spores cannot germinate instantaneously, meaning that moisture must linger for a prolonged time to allow for sufficient growth. Since microwaves function as enclosed spaces, they do not collect humidity or water damage as easily as other household surfaces.
Still, if you allow water to settle at the bottom of your microwave, it may remain present long enough to allow for mold growth. For example, if you microwave a cup of noodles filled with water, some of the boiling water may spill over and remain inside the microwave. For this reason, you should always dry out your microwave and promptly clean up spills.
Mold and Microwave Radiation
Heat is known to kill germs, so you may think getting your microwave hot will solve any mold problems. Unfortunately, microwave radiation does not effectively kill mold spores. While extreme heat from a microwave can neutralize some active colonies, you should not rely on microwave heat to kill mold. Proper mold elimination requires you to disinfect the microwave and remove the spores completely.
Important Health Warnings
If you have mold growing inside of your microwave, do not microwave food until you have thoroughly cleaned and disinfected the inside. Once again, microwaving does not effectively kill mold. According to the Centers for Disease Control and Prevention (CDC), exposure to mold can make you ill, cause respiratory symptoms and trigger allergic reactions. Never eat food that is contaminated with mold or that came out of a moldy microwave.
Cleaning Mold in the Microwave
So while you were on vacation, your teenager left food in the microwave for a week, and now you have a mess to clean up. To start, use a damp paper towel or sponge to remove as much of the mold as you can. Next, Digital Trends suggests mixing 1 cup of water and 1/4 cup of white vinegar in a microwave-safe bowl. Microwave the vinegar mixture on high for one to two minutes.
When the time is up, leave the microwave closed for another two to three minutes to let the steam loosen the dirt inside. The next step is to wipe down the interior of the appliance with a damp paper towel or sightly abrasive sponge. Take a disinfectant wipe to the inside of the microwave after scrubbing it and then dry it thoroughly. Use a damp paper towel to clean the gasket around the door.
Inspect the microwave carefully to make sure you've removed all the mold, If you see mold in a place you can't clean, such as up in the vents, discard the microwave and replace it.
Chris Anzalone has been writing professionally since 2001. He is a former staff writer and associate editor for Opposing Views, a popular news media website that tackles issues of the day from multiple perspectives. Anzalone holds a Bachelor of Arts in English from the University of California at Riverside.