Mold in Microwave

May 2, 2007 10:06 PM

I just found some mold growing in the corner of my microwave.

I'm not a very dirty person so I was quite surprised to see some dark-dark-grey mold growing inside my microwave after I heated up a snack. I'm a little grossed out by it, too, but I quickly cleaned it up as best I could.

My questions:

1. I cleaned it out with 409 because I wasn't sure if bleach was safe for a microwave's interior. Now that I think about it, I wonder if using any chemical inside a microwave is a bad idea. I re-wiped everything with a water-soaked towel, but should I be worrying about fumes or residue that I missed? I'm leaving the door open for now but I don't know how long I really need to do that. I usually just wipe my microwave down with a damp towel...when I clean it, that is. It's obviously been a while since I last cleaned it, and I'm a little embarassed that I only NOW just noticed the mold. :(

2. The mold looked like it had been there for a while (ugh), but I've been microwaving food quite often and eating it and I seem to be fine. So far. But I'm curious now...how hazardous is it to microwave food in an oven that has mold in it? Does microwaving the mold make it grow an extra eye or otherwise mutate into something dangerous? Could the spores have flown around and settled on my food while it cooked? (Or could the microwaves have actually killed the mold? I don't really know much about mold's resilience...)

3. I still see some dark stuff in the crevice where two of the microwave's walls meet. I don't think I'll be able to clean it out. If there is still a trace of mold left in there, and if my concerns in question 2 are legit, do I need to worry about this small bit re-growing? I will replace the microwave in a heartbeat if this mold situation poses a threat to my health, but money is tight right now and if I can safely continue to use this microwave, I will.

posted by anonymous to Home & Garden (13 answers total)

3. To clean tight corners, use an old toothbrush (with whatever your cleaning fluid of choice is).

As to 1 and 2: probably you're ok. I've had mold in the microwave before, and no bad effects from it other than gettni grossed out and ashamed just as you are now. I mean, obviously, try to keep it clean. But don't panic.
posted by LobsterMitten at 10:14 PM on May 2, 2007

Wow, you worry a lot. Sorry that was out loud

I have nothing to say other than that it looks like you missed the absolute easiest microwave cleaning method, viz: just boil a decent amount of water in it for 10-15 minutes. Any dirt will slide right off. You could still do this now, and it'd steam up nicely and presumably deal with any cleaner residue (I doubt it's any sort of health hazard, but if you can smell it, it might leave a slight taste in your nuked food). The stuff in the crevice might come out easily with an old toothbrush after the boiling water, too.

I just cleaned an old one pretty thoroughly, and tried boiling vinegar and water in it. The vinegar fumes were not the most fun, but it did turn it nearly-new in no time.
posted by kmennie at 10:16 PM on May 2, 2007

There isn't anything magic about microwaves. Using a normal kitchen cleaner inside of a microwave oven, letting it air out, and then using it on food isn't going to result in you transforming into the Incredible Hulk.
posted by Steven C. Den Beste at 10:41 PM on May 2, 2007

To prevent mold growth, leave the door open for a bit after using the microwave. How long a bit is depends on how humid it is where you live.
posted by yohko at 11:56 PM on May 2, 2007

its worth remembering that the reasons microwaves have a spinny plate thingy is that they do not heat up everything within the space - the waveforms that actually heat up the contents are not consistent within the space - so rotating the food makes sure its equally exposed.

so your mould could have been happily living there without any exposure to the microwaves. ambient temperature on the other hand could have caused it problems. depends on the humidity and length of time you run the microwave for at a stretch
posted by dnc at 12:28 AM on May 3, 2007

Bleach should be fine on a microwave's interior, and it's hell on mould. Dip a toothbrush in neat bleach, scrub out the mould, wipe out that corner with a wet sponge followed by a damp towel, and leave the door open to air the oven out until you can't smell bleach any more.
posted by flabdablet at 4:48 AM on May 3, 2007

Mix 1/2 cup of white vinegar, 1 cup of water and 1 tablespoon of baking soda in a large bowl. Put the bowl in the microwave without a lid on and cook on high for a few minutes, allowing the mixture to boil, but not boil over, for 1 minute. While the microwave is warm and steamy, wipe the interior down with a cloth. (From Spotless by Shannon Lush and Jennifer Fleming).
posted by Pigpen at 6:16 AM on May 3, 2007 [3 favorites]

Simple Green also works well on mold. I had a dorm fridge that became a beer fridge, and was out of town for two weeks and the breaker tripped...gah, it was nasty, but I just simple greened the hell out of it, hosed it out, and put some new beer in there.

It's mold; Maybe it'll give you some penicillin!
posted by notsnot at 6:40 AM on May 3, 2007

Another home-brewed cleaning method: Put some lemon slices in a cup of water and zap it for a minute or two. Wipe down the surfaces. Repeat.

It's more pleasing than the vinegar smell, and also pretty effective.
posted by Robert Angelo at 6:46 AM on May 3, 2007 [1 favorite]

easiest cleaning method of all: put dripping wet dishrag in microwave. (soapy water or water + cleanser on rag) Microwave on high for about 2 minutes. use rag to wipe out interior (careful, rag is hot)
posted by cosmicbandito at 7:29 AM on May 3, 2007

Microwave ovens, FWIW, don't irradiate food the way you think, which is what I think causing your undue stress over this. It's simply using non-ionizing radiation to heat the water molecules inside whatever you put in it. It's about as far from what we generally consider "nuclear energy" as you can get.

Bottom line, mold in the microwave is no better or worse than mold in the oven, and you deal with it the same way.
posted by mkultra at 8:35 AM on May 3, 2007

Yeah, my microwave gets moldy sometimes, too. On the rare occasions we use it, the steam gets trapped inside, making a cozy little incubator.

As everyone has said: clean it out, then let it air-dry. I've used bleach and water, and never seen any bad effects, but plain old hot water, or a wet cloth sprinkled with baking soda for abrasive power, works fine for me.

Mine has a glass (or Pyrex) tray insert that I can take out and clean in the sink. I do that once in a while as a preventative measure.

I'm not qualified to answer "how hazardous is it to microwave food in an oven that has mold in it?", but I can tell you that my microbiologist brother-in-law has waved off that concern. Of course, maybe he's trying to kill me. I am his sister-in-law.

Heck, I'm allergic to lots of molds, and microwave mold has yet to cause me (known) problems.
posted by Elsa at 8:53 AM on May 3, 2007

Echoing mkultra: don't worry about the microwaves & mold turning into some world-eating super mold. Radioactive spiderbite this is not.
posted by Elsa at 8:56 AM on May 3, 2007