Fate of Escherichia coli O157:H7 in field-inoculated lettuce

► Attenuated E. coli O157:H7 was inoculated onto field lettuce in the Salinas Valley. ► The population size of E. coli O157:H7 declined very rapidly. ► E. coli O157:H7 was detected in lettuce plants by enrichment 4-weeks post-inoculation. ► Irrigation type did not have a consistent impact on the survival of E. coli O157:H7.