What are food safe finishes for woodworking projects, e.g. turned bowls?
There are many different kinds of finishes that are food safe. It turns out most finishes once dried or cured are food safe to one level or another.

Most finishes that cure are only food safe after they have finished curing which, sometimes can take quite a while, days, weeks, for some months.

Many of the food oil finishes are very food safe, peanut and walnut oils for example.  However, these are not hypoallergenic, since people with nut oils can react to the finish in the wood.  Though people with extreme allergies could even react to the walnut wood itself.

Natural waxes are excellent food safe finishes that are also hypoallergenic.  Bees wax is a good one and apparently paraffin is also a good one, even recommended for cutting boards, which means with the knife in contact with the top it, you are sure to get some mixed in with the food.

My favorite wax is Carnuba wax, it is claimed to be the most hypoallergenic wax out there and it is also the strongest/toughest natural wax known.