This is actually pretty easy to figure out. If just the one person/family gets sick, it was probably customer mishandling.
That's open & shut. It ain't complicated.
A lot of the time we find "it was just going around the community" or "it came from X restaurant." In no case does anyone assume "it must've been the farm."
In the US? About 3,000 per year.
What you'd really want to look at is what foodborne illness deaths globally, because that will include areas that *doesn't* have the preventive infrastructure that the US does.
That's the population of Colorado Springs. Just gone. Every year. Because of gross food, which is completely preventable.