Ten product containers were tested for BPA leaching, including a Munchkin feeding bowl and a Stouffer’s frozen dinner. The products were either labeled as microwave-safe or were meant to be warmed in a conventional oven. Not surprisingly, BPA was found leaching from every single product, even containers labeled with recycling codes 1, 2, and 5.
As we discussed before, recycling categories should be used as a guideline to help you avoid BPA, polystyrene and PVC. Products labeled with codes 1, 2, 4 or 5 are not guaranteed to be free of hormone-mimicking chemicals.
And What About Oven Safe Cooking Bags and Microwave Safe Dishes?
When it comes down to it, we just don't recommend cooking in plastic. Period.
Even BPA-free products like oven cooking bags and microwave-safe dishes that are supposed to be specifically designed for that purpose aren't usually stable enough and end up leaching chemicals when heated too much.
We’ll stick to warming our food in glass. Dr. Vom Saal said it best,
There is no such thing as safe microwaveable plastic.