wow that sounds hard,,
me being me,, would try talking to him ( again we don't' know how old he is,, ) but ask him why , or what he thinks is wrong with it? Getting to the bottom of the problem is a good start to fixing it.
I wouldn't eat ravioli for ever because my brother told me it was made with cat meat,, LOL I never ever told my mom that,, but when I got older I found out for myself that that just wasn't true,, so it could be something that he heard and misunderstood or is afraid of.
If he's too little to explain it , then I agree with others,, you can't go out of your way to please him,, he will be in school and have to eat lunch there , even if you pack his lunch, there are snacks and things like that , that he will be faced with,, and then there's always the sleep overs,, and birthday parties,, that he will have to learn to navigate through,, you really don't want him telling the host family he can't eat their food because it isn't fresh?
Good luck!!!