The FDA, along with CDC and state partners, initiated an environmental assessment in the Yuma growing region to further investigate potential sources of contamination linked to this outbreak.
Samples have been collected from environmental sources in the region, including water, soil, and cow manure. Evaluation of these samples is ongoing.
To date, CDC analysis of samples taken from canal water in the region has identified the presence of E. coli 0157:H7 with the same genetic finger print as the outbreak strain. We have identified additional strains of Shiga-toxin producing E. coli in water and soil samples, but at this time, the samples from the canal water are the only matches to the outbreak strain.
Analysis of additional samples is still ongoing, and any new matches to the outbreak strain will be communicated publicly and with industry in the region.
Identification of the outbreak strain in the environment should prove valuable in our analysis of potential routes of contamination, and we are continuing our investigation in an effort to learn more about how the outbreak strain could have entered the water and ways that this water could have come into contact with and contaminated romaine lettuce in the region.