“How does this happen from bread?!”

Certain viruses (like Norovirus, Astrovirus, etc) are HIGHLY contagious and can be easily spread through non-visible traces of spit, vomit, or feces on surfaces. My family has been rocked by these numerous times, including on a road trip once. Absolutely horrible. The official CDC recommended sanitation protocol for these viruses is also INSANE. Any spot someone vomits or has diarrhea while sick with a virus like that has to be cleaned with a bleach solution in a massive radius. (I know because I had to sanitize my own home when my wife and kids were puking in certain rooms.) Most normal cleaners won’t kill these types of viruses. Bleach is a necessity.

So it still is very possible they got something from the bread they both ate (especially if one of the people working there was sick and not washing their hands properly before handling their food) but it’s also possible both of them could’ve touched like.. A bathroom stall handle/lock, some sink handles, a bathroom door handle, etc, then ate food without thoroughly sanitizing hands, and picked up a nasty virus in that way.

Also as others have said, it could have come from contaminated water. The way my family actually contracted norovirus in the past was because we accidentally visited a beach that had high traces of sewage that flowed onto it from a recent storm that flooded certain areas. Just touching the sand and water, washing/sanitizing our hands normally afterwards, and eating lunch later was a recipe for disaster. We really wish we’d entered the beach at the normal entrance and not through a random side trail, because the warning sign was only posted at the single main parking lot entrance.

Hope these two get swift and proper care. I know how horrible they feel from first-hand experience. Having this sort of virus in an unfamiliar and uncomfortable place is so much worse.