Will this have any adverse effects? I've read that since they're made for one time use with a cold products they may melt. I have never had this happen.
What I'm concerned with is some of the plastic leeching into the food. I believe this happens to some extent even under colder temperatures. I'm not sure if it would really reach a high enough temperature to be harmful, because a microwave can't really heat higher than the boiling point of H20 unless there is a bunch of sugar and fat in the food. I use these to steam frozen veggies and heat milk to make yogurt.
I figured some of you would have knowledge on this because re-using these containers is so convenient, and we all lovew cottage cheese.