Butcher blocks and other wooden work surfaces used for food preparation should be cleaned after each use. Use chlorine bleach to kill germs from raw foods such as chicken, fish, and meat. Wash any surface that touches these foods. Then cover the surface for two minutes with a diluted solution of unscented chlorine bleach, rinse thoroughly, and air dry.
You may end up needing to sand the wood surface to remove all the stains, but generally you can renew it, and protect the surface with an edible oil. This is a page about cleaning an old butcher block wood table.
