My local news station just updated the report. They suspect the problem originated from a California processing plant. They also said that washing it does not help. It can reduce the amount of bacteria, but the bacteria clings in the small crevices of the leaf.
A few years ago, I watched a pm magazine show that discussed organic vs. conventional farming. Supposedly, organic has more bacteria.
"Critics argue that organic farming leads to the risk of contamination with potentially dangerous bacteria and mould toxins, and increased levels of ‘natural pesticide’ found in organic produce could even be as dangerous as synthetic chemicals."