Continuing the discussion from Dyeing a Cutting Board Grey?:
By and large aren’t all finishes food safe? In that every finish, including so-called “food safe” finishes, are only “food safe” after completely curing. The process of curing, whether by evaporation/off-gassing or contact with open air/oxidation, is essentially where the poisonous stuff use to dissolve or suspend the actual “finish” disappears, leaving only the protective surface, e.g. (from link at bottom):
Q. How about so-called salad bowl finishes? Are they any safer for use with food? A. We looked at the material safety data sheet (MSDS) for one type of salad bowl finish and found toluene–a probable cancer hazard–along with naphtha, ethyl benzene, and cobalt, all of which can damage your health with sufficient exposure. So, these products are as safe as, but no safer than, any other cured finish.
It’s worth noting that cutting & chopping boards are a specific use case: wood finishes that might come into contact with food include bowls, cups, plates, utensils, trenchers, and countertops. Cutting/chopping surfaces experience a lot of wear-n-tear from a knife (or whatever) and no matter what it is finished with there is the almost inescapable micro-particles from the board that get chopped/sliced up with the wood grain and end up in whatever food is on the board. So even if not finished at all some wood fibers/molecules will end up potentially being ingested.
While I am personally not terribly worried about ingesting a little bit of micro-particles of whatever (geez…the crud we ingest/breath in all day long is enough to make a billy goat puke), this is why I only use wax/mineral oil combinations,which then need to be regularly re-applied, as finish for “working” cutting boards, as opposed to dough-rolling or display or serving boards, e.g. a charcuterie board.