Mineral oil for finish and water and bleach spary for bacteria kill if your preparing food on the surface.

I have been researching this for a customer and the general consensus is that there is no "food safe" stain, meaning that you shouldn't use the counter as a cutting board. If you don't plan on using it that way, then General Finish makes very nice stains and sealers that are both tough and water proof. They also have a very helpful customer service line.