Almost all clear wood finishes are safe, as many of the things that made them unsafe, such as heavy metal dryers, are no longer allowed. And once cured, even finishes with mineral spirits, such as polyurethane, are safe, as the spirits have evaporated. Stains vary - you'll have to check the individual brand. Here is a link to a discussion on food safe finishes:
http://www.woodcentral.com/articles/fin ... 497a.shtml
One thing you may want, which is not usually considered food safe, is something like a marine varnish, as they have UV inhibitors added. However, as long as it is fully cured, the UV inhibitors really shouldn't pose a problem, as they are basically enclosed in plastic, and these kinds of things are usually only considered a health threat in something like a chopping board, or a bowl, which may wear off into the food you eat. In a pot, you shouldn't have to worry about it.