FDA issues an update statement on Yuma E coli outbreak

Earlier this year, a serious multi-state outbreak of Escherichia coli O157:H7 infection was associated with consumption of Romaine lettuce from Yuma, Arizona.

The US FDA has now issued an update statement, though the investigation is not completed.  Tests of canal water close to the lettuce growing farms has tested positive for the outbreak strain of E. coli O157:H7, which is capable of producing Shigatoxin.  Infection with this microorganism can result in serious disease - 210 people in 36 states have become ill, with 96 hospitalizations and five deaths.

No single farm has been determined as the source of the outbreak, nor has the distribution chain been implicated so far.

The lettuce growing farms and canal are close to a Concentrated Animal Feeding Operation (CAFO), which can hold in excess of 100,000 head of cattle at any one time.   Since cattle can harbour the STEC E. coli involved in the outbreak, there is the possibility that the presence of the bacteria in the canal water originated from the CAFO.  Further testing of the CAFO and the animals would be necessary to establish a link.

The means by which the lettuces became contaminated must also be investigated.  Was the canal water used directly for irrigation, or were the bacteria somehow transferred from the canal water to the leaves?