General Finishes makes a salad bowl finish that is non-toxic when cured. I use it when working with items that are going to come into contact with food. If you are wanting to use the paint and sand method I would still finish the wood with the salad bowl finish first. Bamboo is pretty porous and you probably will get some paint bleed up the pores if you don't seal the v carve first. If it was my project and I wanted color I would seal with a couple coats of salad bowl finish, paint with an acrylic hobbyist paint, sand any mistakes outside the lines, then a couple more coats of salad bowl finish. Personally I think just a couple coats of a non-toxic finish should give you enough contrast. If you use this method you still can make that call after the first two coats of salad bowl finish.
You could torch the carving (lightly) with a narrow flame and then sand the flat surface over before finishing with oil. That said, having a carving on a pizza paddle dusted with flour (to smoothly slide off the limp dough) will not exactly improve usability. The flour and overflow tomato sauce will get stuck in the carving or the dough may catch. I usually have to brush off my (uncarved) pizza paddle under running water after use. A vcarve inlay might be better.
lsvien wrote:..... Bamboo is pretty porous and you probably will get some paint bleed up the pores if you don't seal the v carve first.....
Can not really confirm that. While I used bamboo plywood mostly for more practical things like furniture, I tried a few experimental v-carvings just to see how it came out. The dragon below is in natural color vertical set bamboo plywood (your paddle is similar but horizontally set strips) with simple black spray paint filling and the other one is in marbled compressed bamboo (floor panels) with gold spray paint. I did not see much bleeding if any in either experiment. IIRC I did not seal the surfaces before filling the carving.
Most finishes are food safe once they are fully polymerized or 'dry'.
If the bamboo was prefinished before you carved into it, you could use an aniline dye to colour the v-carve, then apply an oil finish. Pure tung oil is completely food safe even before it polymerizes (but does take a long time to polymerize, at least a week per coat).
One of the things you will have to consider is cleaning the peel especially with the carving in it. I would go with pure tung oil which doesn't have additives in it and can provide good protection including some water protection. I make some pieces for a microbrewery to hold glasses of their various brews and they have to put their boards in a dishwasher. They recoat them with pure tung oil after about 3 washings. But their boards go through a much tougher use than yours would unless you are making those for a pizza shop.
Thanks all. I decided to do bowl oil and it showed up great. Always get the right answers here. Thank you. It is for a pizza shop, and I figure they could always use the back side and hang the front side out.