The type of finish depends on a couple of things depending on how you plan to use the piece and how you define food safe. One common thought is that all modern finishes are food safe once cured. In this case you could go with a spar urethane or epoxy finish that would seal the wood and need very little upkeep.
At the other end of the upkeep and durability scale, but indisputably food safe you could use a mineral oil/wax finish (google wood butter). Apply a good coat and repeat daily for about a week then once a week for about a month to season the piece. Then reapply after every few uses. Seems like a lot of work, but it only takes a minute to wipe it on and buff out with a rag. It will work fine for standard use, just do not let the liquids stand in the cup for too long. I use this for the bowls I sell because there is no argument as far as whether it is safe or not. Well almost no argument. Someone once complained he did not want to have food grade MINERAL oil in their food. I guess you could use Walnut oil (possible allergan) or raw linseed oil as a substitute.
A third choice are the salad bowl finishes where companies paid to actually do the testing to certify food safe. These are oil or oil and varnish finishes. If you look at the ingredients on the MSDS, they contain the same stuff as similar products not certified food safe. They are in the middle as far as upkeep and durability.
So the choice is yours.
