I was\am in the business of selling cutting boards (not so much
anymore) and I did my research and the rancid indication comes from
scientific sources (no I don't have the cites right now) but
basicially you are introducing a food for bacteria in the food based
oils. At the micro level you can get some growth which is
characterized as rancidity (word?).

On May 5, 10:49*am, "CW" wrote:
"Leon" wrote in message

...

* My wife has never used anything but vegetable oil on the butcher block
and there has never been a problem with anything going rancid, at least in
the last 30 years. *While mineral oil and or a butcher block oil may be a
better choice, vegetable oil has done just fine for us.

Wesson oil for ours and the same for my mothers. I would bet that most of
the "going rancid" replies are from people that are just repeating what
others say rather than having any experience.