The polyurethane on my kitchen cabinets is turning white.. how can i restore their color.They are natural oak?

Question

it is showing the worst on the grooves that make up the natural imperfections in the wood. it almost looks like soap scum.

It is equal over all the cabinets; It is not just near the stove.

Answer 1

My best guess is that you have high humidity in the house. It is invading the Poly from underneath. Check to see if the inside of the cabinets is sealed with the Poly.

Answer 2

It sounds like a lot of moisture somewhere.
Try 0000 steel wool. That can remove a lot of that, then dry and reapply new polyurethane.