What is actually happening when you stain a plastic container/surface?

Question

If you put spagetti sauce in a tupperware container, the tupperware is seemingly stained orange forever. What is actually happening to cause this? Does the plastic container absorb molecules from the spaghetti sauce which is forever trapped in the polymer chains?

In: Chemistry

Answer 1

The plastic expands because of heat and locks food in when it cools. Wait for food to cool before putting it in a plastic container.