During the second flight, I felt sick.  I don't think it was likely
caused by the salad.  (The only item in the salad that could obviously
go bad was the feta cheese.  But I didn't like the feta cheese and so
didn't eat much of it.)  Rather, the flight felt slightly turbulent the
whole way.  I think my reading at the beginning of the flight gave me a
headache before I noticed the difficulty, and the headache never left. 
And then, near the end of the flight, I felt even worse, but I simply
think that was from low blood sugar.  When I finally had dinner at home,
with lots of soothing white rice, I started feeling a bit better.