[mcaswell]

I've never heard of such a thing - zinc counter-tops. But, hey, what do I know!

Are you sure they are solid zinc, or perhaps steel sheet that is zinc plated?
Stick a magnet on it to check for steel.

I can imagine all sorts of problems with this. Acid materials like vinegar and even tomatoes are going to seriously corrode zinc. Any metal object, like flatware, placed on a wet surface would cause the zinc to sacrifice itself to the object.

If you must have them, I'd suggest you coat them with a tough material that will withstand chemical attack. Our Gas Tank Sealer would be ideal, but at this point, I'm not sure it has FDA approval for food contact.

Interesting. Let us know what you decide to do, please.