https://newfoodeconomy.org/romaine-ecoli-outbreak-cdc-fda/
excerpts:
…combined with its large surface area to absorb bacteria, nooks and crannies that defy washing, and the fact that—unlike E. coli-tainted meat—lettuce is rarely cooked, makes romaine a particularly challenging conduit for foodborne pathogens.
…
After last fall’s E. coli outbreak, the industry groups United Fresh Produce Association and the Produce Marketing Association created a task force to identify root causes of the ongoing contamination. Improved water quality management and testing was the very first recommendation from their final report, as well as a suggestion that the proximity between lettuce farms and concentrated animal feeding operations—commonly called CAFOs—is strongly indicated as a risk factor.
