Couldn't it have been something on the worker's hands?
Not that this makes me feel any more comfortable.
I blamed the cold stone on which they mixed the ice cream with the mix-ins, at first.
Would salmonella on their hands or on the cold stone have allowed enough bacterial growth quickly enough to make us all sick, though?
If it was the ice cream itself, then I thought that would make more sense, since the bacteria would have more time to grow.