I watched a UK tv show where they took fussy eaters to eating classes. It turned out in most cases that the kids had not been allowed to 'explore' the food with their senses, therefore it becomes a foreign item they don't know what to do with. After the classes the kids all ate (or at least tried) what was put in front of them. It's not the case for ever child but it was interesting.

Maybe see your MCHN and ask if they know of anything that can help.