Agricultural workers not washing hands after defecating, animals pooping on produce, natural causes … what?
Fecal based fertilizer perhaps. One should always wash their fruits and veggies…
Not salmonella, but there was an E. coli outbreak a few years ago I recall where an orchard had a problem with deer. The animals were going after the low hanging fruit, and in the process they were knocking down a large amount of that low hanging fruit. Rather than accepting the economic loss from this the orchard chose to pick up many of the falls. Which, since the deer had been in the orchard - were often contaminated by contact with deer dung.
I believe this to be a paper about this situation. Alas, all I can see is the abstract.
As I understand it, it is from contaminated water supplies (from livestock runoff, improper slaughterhouse practices or whatever) that is then used for irrigation.