Maybe the farm workers living under the spectre of ice are less inclined to wash their hands.
https://www.yahoo.com/news/us/articles/fda-upgrades-frozen-blueberry-recall-211742727.html
5-10% of people with certain strains of E. coli develop a life-threatening form of kidney failure called hemolytic uremic syndrome. Young children and older adults are at higher risk.
In developed countries, the overall mortality rate for typical hemolytic uremic syndrome (HUS) is about 3% to 5% with modern supportive care.
https://www.mayoclinic.org/diseases-conditions/e-coli/symptoms-causes/syc-20372058