FDA Updates Progress on Romaine Lettuce E. coli Outbreak Investigation

From the continuing investigation into the multistate outbreak of E. coli O157:H7 illnesses linked to romaine lettuce from the Yuma growing region, FDA issued an update stating that it continues to consider a viable explanation to be contaminated canal water coming into contact with produce. However, it also is looking at an animal feeding operation which is near a clustering of romaine lettuce farms.

On July 31 and August 1, 2018, FDA participated in a meeting of the Leafy Greens Food Safety Task Force that was formed in response to the outbreak that occurred earlier this year. FDA shared preliminary hypotheses from the Environmental Assessment in Yuma to facilitate conversations with state and local officials, industry and local growers on the hypotheses and associated actions necessary to prevent such an outbreak from occurring again.

As FDA has previously stated, samples of canal water have tested positive for the outbreak strain of E. coli and it continues to consider that contaminated water coming into contact with produce, either through direct irrigation or other means, is a viable explanation for the pattern of contamination. But other hypotheses were discussed as well. FDA notes that the canal is close to a concentrated animal feeding operation (CAFO), a facility with a large number of cattle on the premises. The CAFO can hold in excess of 100,000 head of cattle at any one time and FDA traceback information showed a clustering of romaine lettuce farms nearby.  

FDA is examining potential links between the CAFO, adjacent water, and geologic and other factors that may explain the contamination and its relationship to the outbreak. Additional sampling activities will be conducted to further explore and narrow down hypotheses in the near future. The agency’s findings will be detailed in a finalized environmental assessment report which will be made publicly available when complete.