Agree with the others - it’s equally likely to have been something you had 6-24 hours prior, based on the incubation period for most stomach based illnesses. Short term reactions can certainly happen, of course, but it’s worth broadening your horizons rather than assuming it was the most recently consumed meal.

Norovirus can also be a cause, which you could have picked up in the last few days (particularly if traveling internationally)...

In any case, don’t expect Delta to do much even if you do have evidence. In a past case where several colleagues and I were able to identify a particular onboard meal as a potential source, Delta waited over a month to investigate and then referred me to their risk management department rather than actually bothering to look into the issue. They eventually contacted the caterer, but by that point two months later any useful information was long gone. They also claimed there were no other reports of illness, despite my colleague filing one via the post flight survey - after which they admitted they didn’t look at those surveys. All in all a pretty unsatisfying experience, so i’d set your expectations pretty low.