When one says "food safe" It begs the question whether you mean safe for you to put in your mouth, or would a lawyer feel it was safe for you to put it in someone else's mouth.
Basicaly there are 6 materials that spring to mind.
-Non-drying oils, these include stuff like Mineral oil, which is my favorite, since it doesn't have an odor, and doesn't go rancid. These usualy look bad on softwoods, and they can transfer to clothes etc...
-Drying oils, stuff like tung oil, or Watco. The problem here is that many of these contain driers, that are toxic to give them a boost. Pure polymerizing tung oil which is tung that has been heat treated, but contains no additives is my favorite here. Watco is also supposed to be fine (check recent literature) if it has been allowed to dry long enough, like aobut a month and a half. These product finish better, but are stills marginal over softwood.
-Wax, by itself, or over the above oils. Beeswax is the most amazing material, but it needs ot be buffed out to a 1 micro layer so to speak. Harder waxes like carnuba give a tougher finish, but are real hard to apply, unless thinned. I think Carnuba is what they put on Smarties or apples.
-Varnishes. Both chemical and natural. Drying oils taken to the next level. They tend to sit on top of the wood and they tend to be a little thick. One has to choose foodsafe versions, but that is what something like salad bowl finish is.
-Shellac, nature's miracle finish. unbelieveable. The best. Really hard to use.
-Catalyzed super chemicals. Epoxy and superglue. Both can be foodsafe. Epoxy needs to be incredibly accurately mixed however. They use superglue in surgery, and it builds and seals nicely over wood.
Overall, most popular wood finishes are foodsafe if they haven't been poluted with toxic thinners driers, etc...