He is now 21 and remembers being sick vividly. He never threw up and never felt nauseous. It was diarrhea (which did turn bloody after a couple of days) with cramps and fever. ( I was trying before not to get too graphic) Regardless, I didn't take him back out after he got sick and all the signs did point to food poisoning, probably salmonella.
I may not have 6 kids, but I have raised 2 (now 18 and 21) and have seen my share of illnesses. They actually haven't been sick at college either. This was unlike anything either one has ever had including the flu and gastroenteritis, but were usually fairly healthy. Fortunately I was home with them and they weren't exposed to sick kids in daycare everyday who were there because mom and dad had to be at work so they'd send the kids sick, usually loaded up on tylenol. I don't get that. I work now and all my supervisors and co-workers are always able to take time to care for their children. No one ever gets any grief over it. I have a friend who did daycare and she had to send kids home many times for showing up sick or suddenly spiking a temp after 4 hours (when the tylenol wore off). My boys got their fair share of exposure to illnesses through church and playgroups, and pre-school which helped boost their immunities, but most people fortunately didn't intentionally take sick children to those locations.
Holding your breath won't do any good. It's not the ones you know are sick that get you, it's the ones that try to hide it and go out and about like nothing is wrong. The best thing to do is wash your hands before you eat and after the bathroom. Otherwise, like what was said earlier, kids do get sick. That's just the way it is. Parents have to be adults and decide for the child instead of for their pocketbook or their good time and not take them out if they're sick. Sometimes vacations just don't happen the way you want.