What protective clear coat is safest for decoupage that comes in contact with food?

I am making dog cookie jars out of some old canisters to be sold at our fundraiser dinner for our animal shelter. We photographed the dogs and puppies with different back-drops and I'm using some of their photos on the jars (they're really cute). I craft quite a bit with things around the house, and usually I use an acrylic spray varnish, and then coat in verethane. These items are purely decorative however. I was thinking of making coordinating mugs/saucers but I would like for people to be able to use them, and for them to be washable. I know my items are washable with a damp rag, is there anything I could use that would allow them to be submerged in water (like a sink) or dishwasher? And if so, what is the most durable clear-coat (epoxy, varnish, etc) that can come in contact with food or beverage? Thank you, any help greatly appreciated!