This is one of those threads where I suspect the child hasn't entirely accurately reported what was said.
Probably some comment was made, which made the child feel sensitive.....but I doubt it was as extreme as reported here.
I think we are too quick to assume that children report everything entirely accurately.
It would seem to me that something was probably said, but in all likelihood a brief, light hearted comment about what they had for tea last night. Perhaps it was a bit insensitive......but to be honest, I would think that was all it was - said quickly and lightly, without intention to hurt or cause awkwardness, and probably not as extreme as 'quoted' here.
Would I be following this up? Absolutely not! Because , there will be bigger battles and adults and children too need to learn to distinguish between big deals which need a battle and those which don't need a battle and just to be moved on from.
And children need to learn to cope with this kind of thing and not be overly sensitive. There is a big difference between a passing remark what isn't intended to be hurtful and something said with the purpose of wounding. Even if the teacher was a bit insensitive, I don't imagine anyone on here thinks the teacher intended to wound. If I was the OP, I wouldn't behave in an outraged way about this. Instead I would just say something about that being a little insensitive, that it wouldn't have been intended to hurt her and that she should just forget it. I think this can teach the child real skills of resilience, because this issue really wasn't a big deal.
However, going into the school and complaining and demanding apologies etc teaches something else.....that it's good to complain about minor things and to make a fuss. It teaches that it's good to take offence easily and to react, rather than move on and be resilient.
And please hear that I am not saying parents should never complain to schools. Of course there are times when it is right to approach school, to find out what really happened and if necessary to complain (once all the facts are established, not before).....but it's really important to get a sense of perspective as parents and not to get incensed over the little slights at happen all the time and really aren't a big deal in life. How we respond to those little slights and issues affects how our kids will respond and if they let the little things get them down and become big issues...or are able to just forget it an.d move on.
Possibly not quite accurately reported. Regardless, not malicious and not worth doing anything about. Move on.