Here's the science bit (in the link www posted)
I used for milk. Why not if shake it first???
By JJ on Wednesday, 24 April, 2002 10:58:41 PM
Tinker, nope, no problem. This is much better than, say, cleaning the toys up in the oh so messy reception room.
Re: microwaves cooking the food after it's been taken out of the oven. Foods will continue to cook after being pulled out, but not by microwaves. This has to do with the hot spots and cold spots. Heat will transfer from a hotter object to a cooler object when they are in contact. So the hot spots will cook or begin to heat up the cold spots (this process, incidentally, is known as conduction). The hot spots can get really hot! When I microwave I usually give the food a rest for a minute or so if I can't give it a stir, just to let the heat even out throughout the food.
Re: hot foods. I don't know about very hot food, except the obvious it-can-burn-you type thing. Microwaves can superheat liquids (eg water), so you have to be careful about that. You don't want to get boiling water all over your hand! But the food isn't dangerous after it's cooled down to a reasonable temperature.
Re: yummy charcoaled bits. The carcinogenic charcoaled bits are the best part of any barbecue, I think! Truthfully, I don't know anything about them either. You're much less likely to get them in a microwave as it generally cooks a piece of food all at once. There's no making a nice, seared on the outside, bloody on the inside piece of lamb in a microwave.
Re: cold food. A botany teacher I once had was a big proponent of the whole natural, uncooked diet. He believed that any cooking killed natural somethings in the food. Again, I've no idea! He looked young and energetic for an old guy, although he had an unhealthy obsession with David Attenborough.
At any rate, the last three concerns you mentioned would relate to any form of cooking. The first is a quirk of the process.
I do think microwaving vegetables preserves more vitamins than boiling them senseless. Some vitamins are water soluble and will leech into the water used to cook them. That having been said, I rarely cook veggies in the microwave as I can't pop one out every now and then to see if it's done yet.