I don't know the specific answer, but I'd suggest that if you're flying coach, whatever snacks they have are going to be pretty underwhelming. If it were me, I'd pack food. If you'd otherwise eat the airplane food but don't want to do it because everyone will be coughing on you at the same time while they eat theirs (which makes complete sense!), you might be able to just let the FA know when you board that you're keeping a mask on for medical reasons and could they hold your meal until after everyone else is done. I'm pretty sure at that point they're heating up crew meals and such, and since your concern is medical, I can't see why they wouldn't accommodate you. But I'd really pack something as a backup - FCO T3, where you'll very likely depart from, has a good amount of decent options (or at least did, last time I was there).

From their official site: https://www.adr.it/web/aeroporti-di-...&p_p_mode=view
That has a link to the PDF below with a map and all of the food options in T3-E (where long haul non-Schengen flights would board from):
https://www.adr.it/documents/17615/2...=1638265225670