Just to show that you can never tell who is going to be upset by what you eat - and bardos please ignore this post as it's not about you!
I am allergic to coffee, even the smell makes my stomach churn. It's been like this all my life and it's not difficult to avoid. Except ... I recall a BD from LHR to Scotland in 1998 and BD were showing off their new wonder breakfast in Biz. Good food and large cups of steaming coffee to rival what the likes of Starbucks were offering at the time.
I was enjoying the meal a great deal when the bloke next to me got one of these coffees. He slurped and then turned to me to say how wonderful it was and waved the mug in my direction and I had to grab the cloth napkin and hold it over my face to prevent myself delivering my breakfast to him in a way that would spoil the start of the day for both of us!
Tin of sardines? I wouldn't mind - just keep the coffee away.