Creating Textures and Bump Maps

I've heard said that food is on par with humans as the most tough things to create in CGI. I have no idea how to approach making food in renders look believable. I don't think I've seen a making food course on Cg Cookie ever either, and now that I think about it, there isn't much of that out there on doing 3D food. Maybe people just rather take photo of food? There's not much CG food in movies either? Maybe other people will have better info on this.