I heard from a friend that if nothing covers the bowl or plate of food, there is a direct radiation affect on the food you eat. Is that true?

  • 5
    Don't believe that friend with anything that has to do with physics, it seems they are mixing up very basic concepts.
    – rumtscho
    Feb 2, 2018 at 8:10
  • 4
    It's probably worth mentioning that, while it has nothing to do with radiation, covering or wrapping your food in the microwave is still a 'good idea'. It's just more about containing splatter and keeping the microwave clean than safety.
    – Cos Callis
    Feb 2, 2018 at 11:45
  • 1
    @CosCallis That's an answer, and the point seems to be made by the current top answer already. If you feel it's not clear enough there, please suggest improvements or post your own answer.
    – Cascabel
    Feb 2, 2018 at 15:41

1 Answer 1


Many plastics used in the kitchen are unsuitable for use in contact with hot food, whether wrapping it or sagging onto it when used as a cover. Freezer bags are a relevant example. These may melt, or leach into the food. I don't worry about this as much as I probably should; some people are very cautious.

A sealed wrap is also a bad idea, as it can burst under steam pressure. For example leaving a bag clipped shut. This is rare though, and also applies to an unvented cover of cling film.

A loose or vented cover is a good idea for keeping the microwave clean.

Your friend is misguided. Microwave ovens use a form of radiation similar to radio waves, and this is what heats the food. It's very different to ionising radiation which we are rightly cautious of.

Microwave radiation isn't blocked by anything you'd use as a microwave cover/wrap, because then your food wouldn't heat up. So it's a good thing your friend's cover does nothing. Microwave radiation is blocked by metal, including the mesh in the door. The emission of microwaves stops instantly when you open the door, because we're made of meat and would cook quite easily (plus the WiFi would be jammed).

All links are from Wikipedia and are further reading for the curious.

  • I'd suggest adding a sentence or two about microwave radiation not being the same as ionizing radiation, else this answer can freak out people for no reason.
    – rumtscho
    Feb 2, 2018 at 8:12
  • @rumtscho, done. I thought my radio waves note would be sufficient but a second opinion is always good.
    – Chris H
    Feb 2, 2018 at 8:27
  • Thanks. I simply think that if a person finds the original claim plausible, then there is a chance they don't know the difference, so a mention of radio waves can be insufficient. Better err on the side of more explanation :)
    – rumtscho
    Feb 2, 2018 at 8:39
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    I appreciate the edit... not knowing that there's multiple types of "radiation" changes how I view things. :)
    – Catija
    Feb 2, 2018 at 15:05
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    Many microwaves do leak some energy, which you can detect precisely because your WiFi gets jammed. It's not enough to cook you, but enough to interfere with the 2.4GHz signal.
    – mattm
    Feb 2, 2018 at 15:52

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