First off.. You have reason to be afraid of microwaves.. I have done some reading and microwaves actually radiate out all nutrition from any food you nuke, if you must reheat, use the oven or stove.
Secondly, Ziploc bags, though they keep food fresh, do spoil the air contained within.
If you have to wrap something up to save it, try using wax paper, it holds for just as long, is much cheaper and no change in food taste. Also biodegradable.
Just some info for those who care from someone trying to live organically.