I oiled our old wooden table and kitchen island recently. It had many months.
With a new baby and toddler in the house who often eats off these surfaces, I used edible organic Jojoboa oil.
I'm sure there's many other non-toxic oils that would work, such as Canola (used on metal farm tools I've heard).
Do you readers have any other suggestions for the comments below?
I put the oil on heavy, and then let is soak in for a about two hours before I wiped off the excess.
The silver lining I realized later, was that left over food bits are so much easier to wipe off! Duh, I know, but it had been a long time since I really did this in earnest with enough oil.