Food poisoning is caused by bacteria that collects or forms in food product(s). It is also caused by unsanitary conditions, not washing hands properly, contact with raw meat, etc. There is no cure for it, it must run it's course. It always grosses me out to go into a restaurant, and use the restroom only to find the sink DRY, (the obvious sign that NO hands had been washed) and I know that it is the only restroom in the building. This tells me that one of two things are happening. 1) NO female employees ever GO to the bathroom, or 2) They are not washing their hands. I would so love to believe the first one, but sadly the second one probably is the case.
Food kept too warm, or not heated enough, grows bacteria that can upset your stomach & digestive system. Unsanitary habits are a cause as well. (Employees not washing their hands after bathroom use, trash disposal, cleaning.)