Vegetable oils can turn rancid, so their use on a food preparation surface is not advised.
I’ve heard this, but I’ve also run across a number of folks who say they’ve used vegetable oils for years without any problems.
I’m sticking with walnut oil.
Another vote for mineral oil. I used to work in a shop that (occasionally) made wood countertops, and the only thing we used was mineral oil.
The trick in finding it is to go to the laxative aisle. When you buy it in the form of “digestive lubricant”, it will be unscented and one tenth the price of “baby oil.” Also, you can buy “butcher’s block oil” which is just 100% mineral oil but at 20x the price.
Flax meal can go rancid. Can flaxseed oil go rancid too?
Rancid is a bit of a funny term when applied to hardening oils like flaxseed.
The oil won’t develop a nasty smell, but it will oxidize, which is a part of the polymerization process that makes it such a nice coating for wood. It also happens to be part of the process by which some oils develop funny smells: become rancid.
Walnut oil is also a hardening oil, and good for cutting boards.
Corn oil is a semi-drying oil, and will leave a gooey buildup on your board after repeated application.
I use mineral oil when I think to oil my cutting board. That does not dry.