If Warmed in microwave are onions toxic?

Question

I was told by my mother in law that if tomatoes and onions are warmed in a microwave they become toxic, even in like chili and other foods that are cooked with them. She said that you are not suppose to reheat onions or tomatoes, like in salsa she said it cannot be warmed up. Is this true? Because I have always reheated chili and other food that had onions and tomatoes.

Answer 1

I believe your mother in law is mistaken.  Foods, especially garden vegetables are all cooked and reheated numerous times.  examples would be any pasta sauce and any of your prepared foods.  They are all cooked in a processing  facility just for you to take home and reheat (cook).  

Answer 2

That's completely untrue.  

Answer 3

While the food won't become toxic, here's an article on lead being leeched from ceramicware by chili and other foods:

http://www.sciencedirect.com/science?_ob...

So if you watch what you're microwaving in, the food won't become toxic.