my son and some of his friends were ill a couple of weeks ago and we have narrowed it down to a communal dish of sweets on the bar at the club he goes to. I tried to find a list of diseases that such things can cause by Googling but couldn't see anything about it. any ideas?
People stick their (unclean) fingers into bar snacks, and they don't just touch the items that they eat, their mucky fingers also touch the other ones, leaving the next dibbler to pick up the germs.
The actual sweets might not have been the cause of the problem. If, for example, one of the bar staff had been handling raw burgers and then (without first washing his hands) grabbed a few sweets, he could have transferred campylobacter bacteria from the burgers onto the other sweets.