Summary of Awards to Date

CPS Rapid Response - Yuma Valley


Jan. 2, 2019 - May. 31, 2019

Amount Awarded



Channah Rock, Ph.D.
University of Arizona



Recent outbreaks in fresh produce coupled with heightened media coverage, have elevated produce safety into the forefront of public attention. More specifically, the 2018 outbreak involving romaine lettuce grown in the Yuma region, was linked to Escherichia coli (E. coli) O157:H7, in which agricultural water was suspected as the source, yet the origin and environmental distribution and potential reservoir(s) of the outbreak strain remains unknown. In response to the outbreak, the California and Arizona Leafy Greens Marketing agreements adopted revised metrics in an effort to address the possible role of atmospheric deposition (dust) and water quality on crop contamination. Revised metrics now require growers to treat their irrigation water if the source passes within 400 feet of a Concentrated Animal Feeding Operation (CAFO) of 80,000 head or more and also if they are using overhead irrigation during certain growth periods (pre-germination, last two weeks before harvest, etc.). Additionally, the set-back distance from CAFO’s of the same size was extended to 1,200 feet, from a previous 400 feet. Exacerbating these concerns, new Federal regulations released by the U.S. Food and Drug Administration (FDA) as part of implementation of the FDA Food Safety Modernization Act (FSMA), impose new requirements on growers to improve food safety and include testing of agricultural water quality for generic E. coli. Many of these rapid changes within a reduced time frame for implementation as well as the findings included in the FDA Environmental Assessment (FDA 2018), which questioned the value of indicator E. coli testing of agricultural water, have left industry with many unresolved questions as to how best to improve their food safety standards and practices.


The overall objectives of this rapid response research effort are to capitalize on the unique opportunity to study romaine production under real world conditions within close proximity to potentially implicated fields from the 2018 outbreak. This venture will allow the research and extension team to generate new knowledge that is useful to industry in order to bridge the gap created by the recent outbreak. The team proposes to focus on the areas of water treatment, persistence of microbial contamination on romaine, as well as sampling protocols appropriate for the detection of indicators and pathogens in commercial scale agriculture.