I'm pretty paranoid when it comes to finding something foodsafe. Be warey of 95% of sealents. Butcher block sealer is wonderful. If you can find a foodsafe shellac or varn that doesn't deteriorate under high moisture... the really light blonde flake style shellac is the most water proof I do believe.

Or beeswax, its slightly less water proof but it works. I've sealed cutting boards and kitchen stuff with beeswax and mineral oil together. Works wonderfully