Feeling irked

[Pedestriana]

Planning a party for my child. Sent invites around with an RSVP date and a clearly-worded "please advise if your child has ANY food allergies". I am catering the party myself.

Started food shopping yesterday. Bumped into grandparent of one of the children who has accepted,and mentioned flapjack & trail mix. Grandparent says "Oh, X can't eat that. He's allergic to nuts. He had pistachios last weekend and we had to call an ambulance."
But I had had no warning from the parent to advise of this.

I then send a round robin email to the other parents who'd accepted. Guess what? Two more say their children have nut allergies.
So because they'd not replied properly, I could've killed their children.

Not feeling happy as I've effectively wasted money on food that's not going to be eaten for H&S reasons, and because this to me is parents not being responsible.

I think you're rather overreacting. Had all the parents RSVP'd?

I don't think the OP is over reacting, more that she seems to be more concerned about these children's health than their parents are

People are a bit shit with invitations; I suppose I'm jaded after 12 years of it. I see SOME lovely parents who read and respond to invitations within a day and many more who don't and then the day before the party, tell you "Oh X can come to the party and he's severely allergic to nuts."

They're idiots and rude...but the best way to proceed (I've learned) is to always provide a nut free meal...and some fruit so if children who can't have eggs turn up then they can have that with jelly.

Yes, everyone has RSVP'd to say their child can come. I am concerned that I might inadvertently give something to a child to eat that will cause a severe reaction because their parent/s did not respond to the part clearly printed on the invitation which asked to advise of any allergies.
It was directly under the RSVP part and in bold font. Not easy to miss.

I do have nut-free options (in fact the only thing that I think has any in is flapjack) but one of the children has a very severe allergy and can not even have 'may contain traces' foods.

That's what I'm "overreacting" about.

I wouldn;t have flapjacks anywhere near him tbh. His parent is obviously a bit dim not to have told you!

They should have told you. Perhaps they are bringing food for their child otherwise they are irresponsible.

Food is provided. By me. Nobody other than the parents of a child with a severe allergy have suggested bringing anything. I've liaised with her to ensure that everything is as safe as possible for her child to consume. I'll double-check the flapjacks.