Highly acidic foods such as tomato sauce or fatty foods like beef gravy are the main concerns.
"People have been concerned that chemicals called BPA and Phthalates that are in ordinary plastic containers and wraps can get into our food when heated," said Toni Hope, Good Housekeeping.
So Good Housekeeping conducted a test to see what would happen.
They sent food in storage containers, wraps and bags to an independent lab to see if chemicals from the containers and wraps would leech out.
"The good news was that we found nothing leeched into our foods," said Sharon Franke, Good Housekeeping.
Those who still have concerns can store and heat their food in glass or ceramic containers. You can also make sure that any plastic wrap you use doesn't touch the food.
The recycling codes on the bottom of plastic containers indicate what chemicals are used. A number 7 means it may have BPA. A number 3 means it may have phthalates.