The U.S. Food and Drug Administration Feb. 13 completed its investigation of the November 2018 outbreak of E. coli O157:H7 in California-linked romaine lettuce.

In a joint statement, FDA Commissioner Scott Gottlieb, M.D. and Deputy Commissioner Frank Yiannas said the investigation showed FDA and the U.S. Centers for Disease Control and Prevention acted quickly to protect consumers by issuing a public warning and recommending that industry and retailers voluntarily remove the product from the market.

“It was critical to provide this advice because it was believed that contaminated produce was still in the food supply at a time when Americans were preparing meals to celebrate Thanksgiving,” the statement said. “By removing potentially contaminated products from the market, health officials and industry were able to reduce additional illnesses.”

The investigation, which included FDA, CDC, state partners, the Public Health Agency of Canada and the Canadian Food Inspection Agency, implicated one source of the outbreak: Adams Bros. Farming located in Santa Maria (Santa Barbara County), California, according to a report in Food Safety News.

At that farm, investigators found an environmental sample that tested positive for the presence of the outbreak strain of E. coli O157:H7. While there is no evidence to indicate that this farm is the sole source, the outbreak strain of E. coli O157:H7 was not detected in any other samples collected during this investigation.

The overview reveals:

Adams Bros. Farm, identified in multiple legs of the U.S. and Canadian traceback investigations, was also identified as one of the potential suppliers of leafy greens or romaine lettuce associated with a 2017 outbreak.

FDA concluded that the water from the on-farm water reservoir where the outbreak strain was found most likely led to contamination of some romaine lettuce consumed during this outbreak.

Traceback investigation analysis indicated that other ranches owned by the same farm as well as other farms may have introduced into commerce contaminated romaine lettuce or other produce items. These other farms did not use water from the water reservoir where the outbreak strain of E. coli O157:H7 was found and FDA was unable to identify a potential source of contamination.

FDA has concluded that the water from the on-farm water reservoir where the outbreak strain was found was most likely not effectively treated with a sanitizer and this may have led to contaminated water directly contacting romaine lettuce after harvest or by the washing and rinsing harvest equipment food contact surfaces.

FDA does not know how and when the on-farm water reservoir became contaminated with the outbreak strain. No evidence was found to identify and confirm an obvious route for on-farm contamination, or from adjacent land, to the on-farm water reservoir. Other explanations regarding how the on-farm water reservoir was contaminated with the E. coli O157:H7 outbreak strain aside from the potential contributing factors identified in this report are possible.

Foodborne illness outbreaks caused by this specific strain of E. coli O157:H7 occurred in 2016, 2017, and 2018, indicating that the outbreak strain may have either persisted in the environment or may been repeatedly introduced into the environment from an unknown source. Public health officials in the U.S. and Canada were unable to definitively confirm the food vehicle and ultimate source(s) of the 2016 and 2017 illnesses.

Rep. Rosa DeLauro, D-CT, chair of the Congressional Food Safety Caucus and a senior Democrat on the Agriculture Appropriations Subcommittee, which has jurisdiction over funding and oversight of the FDA, released a statement reacting to the FDA’s findings saying, “For all the agency’s bluster on improving traceability, the FDA has done little to advance real actions that would prevent food outbreaks in the first place.

“The FDA’s investigations into last year’s romaine lettuce recalls have confirmed what we already knew to be true: dirty irrigation water contaminates produce and makes people sick. The fact that people are dying and lives are being destroyed while the FDA caves to big corporate interests is unconscionable.

“FDA must take its own findings to heart and implement science-based standards to test irrigation water. Eight years after the Food Safety Modernization Act was signed into law, it is long past time these important rules went into effect—not delayed into the next decade. Enough is enough.”

Investigators positively identified the outbreak strain in the sediment of an irrigation reservoir on the implicated farm. These findings build upon FDA’s Environmental Assessment into last year’s E. coli outbreak linked to romaine lettuce produced in the Yuma growing region, DeLauro’s statement said.

“That investigation also positively identified the outbreak strain in contaminated irrigation water, which was found in three separate locations along an irrigation canal used by multiple farms,” DeLauro’s statement said. “Together, both outbreaks resulted in 272 illnesses, 121 hospitalizations and five deaths.

“Despite scientific evidence that contaminated agricultural irrigation water poses serious risks to produce safety, the FDA is continuing its proposal to delay implementation of the Produce Safety Rule’s testing requirements of agricultural water under the Food Safety Modernization Act. The original compliance date was set for 2018. However, under this policy FDA will not begin any enforcement of these rules until at least 2022.”

The outbreak, which sickened 62 people in 16 states and the District of Columbia, was declared over in the U.S. by the CDC on Jan. 9.

Larry Dreiling can be reached at 785-628-1117 or

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