For reporting purposes, I would begin with a call to my local health department. They should be able to tell you which "authority" would have jurisdiction, since I personally am not sure if it would be the departure city or the arrival city. I would also notify the airline as well as the catering company (don't rely on the airline to inform the vatering company, they should, but I wouldn't bet the farm on it!).

I would urge everyone to ALWAYS report food poisoning (or suspected food posioning) to the health department. Even if only to help them identify the source of a potential outbreak.