Most cases of human disease linked to fresh plant produce consumption involve bacterial faecal contamination. Both manure and irrigation water have been evidenced to contribute significantly to the spreading of human pathogens to fields and crops. A variety of human pathogens have been shown not only to attach to and proliferate on the surfaces of plant tissues, but to survive and multiply also inside plant tissues. The largest reported vegetable-borne outbreak to date, which occurred in Japan in 1996, was caused by E. coli O157:H7, and in 2006 the same pathogen triggered a spinach-linked outbreak in the U.S. Besides pathogenic E. coli, investigations within PathOrganic are centred on Salmonella enterica, which has been isolated from many types of vegetable such as lettuce, seed sprouts or melon. Other pathogens of concern include Campylobacter spp., which is frequently found in the farming environment, Listeria monocytogenes, commonly found on decaying plant matter, and Staphylococcus aureus, which incidentally has been detected also in plant produce.