Re Allergies
Speaking as someone who is asthmatic and highly allergic to cat hairs (yes I know thats oversimplifing things a bit - the pathology of the allergic reaction process is highly complex) - I don't think that the smell of a burger bar meal could trigger an allergic reaction ?. Traces of nuts or hair on a passenger seat, headrest or other part of the cabin could. The smell of the afformentioned takeaway might be unplesant to other people and its probably bad manners to bring tucker aboard for this reason. So its best to eat the food at the terminal. People suffering from allergies or those responsible for children suffering likewise, need to take suitable preparation and care. I'm speaking from experence.
So no chance of me bringing one of my homemade Mung Bean & Lentel Vindaloo's onboard.
Being serious again (Re allogens of any type ) inform the CC quickly, if you think there's a problem.
CAT III (The thread is actually an interesting one.)