Reply by Tennessee

Spalting is actually a fungus that is starting to grow in the wood, and a percentage of the population is allergic to it. If you have a worm-hole, it could be anything from a beatle to a termite. Finish or not, if you find dust around the piece in the next week or so while keeping it on a clean surface in a temperate climate, not only do you have fungus in the spalting, you have live things…
And since a cutting board is meant to be cut on…sooner or later someone will go through your finish and expose the fungus and whatever else is in there. Sorry.

-- Paul, Tennessee, http://www.tsunamiguitars.com