Pesticides are used on organic food too. Often they use much larger volumes of less effective pesticides to compensate.
https://en.wikipedia.org/wiki/2011_Germany_E._coli_O104:H4_o...
Using epidemiological methods the outbreaks in 2011 were traced to a shipment of seeds from Egypt that arrived in Germany in December 2009.
Citing as a source:
http://phys.org/news/2012-02-insight-whole-genome-sequencing...