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Do high power microwaves ionise water molecules and/or rearrange food molecules?

  1. Oct 12, 2011 #1
    Ok, this is a separate topic about Microwaves.

    I have come across claim that microwaved food is safe for health as long as the food is microwaved on a low power.

    This is because microwaves oven that are used on high power can strip ionise a water molecule and rearraange atoms in food, which changes their molecular structure.

    If this is so, then should we not only use microwaves on low power ONLY?


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  3. Oct 12, 2011 #2


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    Let me ask: Are you willing to give up on grilled food and fried food? If not, any worries about microwaves are absurd. The tendency of the former to create carcinogens is well established. The tendency of the latter to create harmful chemicals in actual cooking has never been established.

    FYI: I have no intention of giving up grilled food, or microwave food.
  4. Oct 12, 2011 #3


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    PAllen has a good point. All cooking will cause chemical reactions in food. That's kinda the point. But they aren't very discriminate about it.

    For example, any time you burn something (like in an oven, stovetop or BBQ), you are creating PAHs (poly aromatic hydrocarbons), which are known carcinogens.

    Very difficult to burn something in a microwave.
  5. Oct 12, 2011 #4


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    Only if you want to die from the salmonella, listeria, e.coli, etc, that will survive your undercooking.
  6. Oct 12, 2011 #5
    i would just say heat things slowly, especially if there is a lot of oil or fat. microwaves do not just heat water molecules. and unlike water, fats can have boiling temperatures much higher than 100C. i think this is much of the reason food that is "nuked" on high often tastes bad. it also can screw up your plastic containers.

    i don't "cook" anything in a microwave, save popcorn. and what i reheat, i do slowly so that i do not overheat the fats, and the taste doesn't come out mangled.
  7. Oct 12, 2011 #6


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    I do believe that plastic food containers are not designed for microwaves. It blisters them in who knows what kind of chemical reaction.
  8. Oct 12, 2011 #7
    i think the damage is from overheated fats.
  9. Oct 12, 2011 #8
    The power setting on the microwave only changes the intensity of the microwave radiation, NOT the energy per photon. So, no matter how high the microwave setting, it's the same photons coming out, just more of them. No matter how many of these low energy photons you shoot at water molecules, none of the molecules will be ionized (at least not directly from absorbing a microwave photon. I don't know of any microwaves powerful enough to jiggle the water molecules so much that it turns into a plasma.)
  10. Oct 12, 2011 #9


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    Well, there is a difference between taste and health (though I never heat in plastic containers at all, based on leaching from the plastic). In no way would I claim it is certain that microwaves can't produce harmful chemicals during cooking, just that it has never been established, while it has been established for several other cooking methods that are delicious.

    In pyrex, porcelain or microwave safe ceramic containers, I've not had any problem with fats (taste or otherwise), but definitely avoid warming breads or pastries in microwave, purely due to adverse taste and texture. In a pinch, I do pizza slices, but the crust is always ruined in taste and texture.

    As for power, I use high to heat liquids, medium-high for most other food, low for defrosting.

    As for cooking, I think the only issue is flavor. Flame based cooking tastes better, but I suspect is more harmful than microwave cooking. There is only one Indian stew I currently cook in a microwave.
  11. Oct 12, 2011 #10


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    The observation of this principle is, by the way, that for which Einstein earned his Nobel Prize.

    Note that the infrared and visible radiation from a red hot heating element in a conventional oven has more potential to ionize molecules in the food.

    Now if you put flecks of metal in the food and let them arc in the microwave you might get something going that way.
  12. Oct 12, 2011 #11


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