I am a long time woodworker. Mostly Wood Turner now.
This question comes up alot on all of the woodworking message boards I follow.
Mineral Oil is nothing more than highly refined (filtered) motor oil. It is inert. It also never dries (Hardens). It is food safe and is used to "exercise" your internal plumbing. It is a common cutting board finish.
Pure Tung Oil. Expensive and hard to find (True Tung Oil). Takes very long time to cure. 30+days each coat. Great finish but not fast.
Refined Walnut Oil (Heated) will cure. There is a very popular woodturning finish maker named Mike Mahoney. He produces a line of food safe finishes that many folks like.
Wax. Not really a good choice for a finish. It provides no protection to the wood. It can provide a quick shine that many folks like but over time it will soften with humidity and get a muddy look to it.
There are several "Salad Bowl Finishes" produced commercially. Any of these would provide a good finish for a cutting board but they do get expensive.
The rule of thumb that most of us woodworkers use is that all finishes are food safe once cured. Generally this means if you can still smell a solvent odor it is not cured yet. Nearly all Modern finishes contain so little PPM of any harmful ingredients that safety once cured is not an issue.
That being said if your ButcherBlock was coming out of my shop I would finish it with Mahoneys Walnut oil. I get from Craft Supplies USA
http://www.woodturnerscatalog.com/store/Finishing___Food_Safe_Finishes?Args=
Or if it was a show piece (not for use) I would finish it with my homemade varnish mixture of 80% mineral spirits-20% Pettit Captain's Varnish #1015.
http://www.pettitpaint.com/catalog_browse.asp?ictNbr=61
3 Coats and buffed out it looks amazing and has UV protection and good wear.
Best of luck,
---Nailer---
