3. Conclusions

  • The number of outbreaks of foodborne disease linked to the consumption of fresh produce has increased since the early 1990s.
  • O157:H7, previously associated with illness from foods of animal origin, cause the highest proportion of fresh produce-linked epidemics that have a known etiologic agent.
  • Surveillance data have provided strong evidence for the presence of enteropathogenic bacteria on fresh fruit and vegetables.
  • Not all enteric pathogen species are ecological generalists. Large differences exist among various enteric pathogens in their ability to attach to and colonize plant surfaces, and particular phenotypes play a role in some of these differences.
  • Although the fitness of S. enterica on plants is relatively weaker than that of common plant-associated bacteria, this human pathogen can grow on plant surfaces under conditions of high moisture and warm temperature, two factors that affect its competitiveness in that habitat.
  • Several studies performed in growth chambers and in the field have demonstrated that S. enterica and E. coli inoculated at planting time persist on crops for prolongedperiods of time, including until harvest.
  • Diseased plant tissue may provide a nutrient-rich and protected ecological niche for enteric pathogens. However, this opportunity for growth is dictated by the nature of their interactions with the resident plant microflora.
  • The expression in enteric pathogens, of survival determinants or of virulence traits in the plant habitat, may modulate the dose–response relationships in the human host and allow for foodborne illness to occur with low infectious doses.
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