Mechanisms of enterohemorrhagic Escherichia coli spread along the food-chain and precautionary measures

Enterohemorrhagic Escherichia coli (EHEC) are food-borne pathogens implicated in large outbreaks and sporadic cases of bloody diarrhea and the hemolytic uremic syndrome. The main reservoir of EHEC is the intestinal tract of ruminants, in particular cattle. Feces containing these bacteria may act as a source of contamination for the environment and particularly for a variety of foods. E. coli O157:H7 as well as other EHEC-serotypes have been isolated from domestic ruminants and non-ruminant farm animals as well as products produced from them, but also from drinking water, vegetables and dairy products. The main transmission pathway of the pathogens is the ingestion of raw or undercooked contaminated food but human infection can also occur by person-to-person transmission. This article will focus on the prevalence and spread of EHEC by vegetable foods, especially the less common EHEC transmission sources sprouts and leafy greens. It will discuss precautionary measures against the spread of EHEC in food at all stages of the food chain: the primary production, the industrial processing, the retailing as well as the consumer.