A Food and Drug Administration report on an E. coli 0157:H7 outbreak traced to California romaine offers no smoking gun into how and where the pathogen was transferred to the lettuce and distributed to numerous outlets.
The report, released Feb. 13, says that of more than 150 samples from numerous farms in coastal California counties, only one tested positive with the same “rare genetic fingerprint.” That was from a reservoir in Santa Barbara County, used by Adam Bros. Farming Inc. As the FDA previously reported, that single source does not explain the scope of the outbreak.
The most likely way romaine in an Adam Bros. field was contaminated was by using the reservoir for “agricultural water.” But the reservoir was not used to irrigate other fields in the growing region, according to the FDA. The investigation indicates that other Adam Bros. fields, and produce from other growers “may have introduced into commerce contaminated romaine lettuce or other produce items.”
Adams Bros. was not only identified in “multiple legs” of the fall 2018 U.S./Canada E. coli investigations, it was a potential supplier for leafy greens/romaine in a 2017 U.S./Canada E. coli outbreak, according to the FDA.
In a summary of the investigation, the FDA reported:
- The Adam Bros. reservoir most likely led to contamination of some romaine;
- Other fields, including those owned by Adam Bros., did not use the same water source, but may have been a source of tainted lettuce;
- Water from the reservoir 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/rinsing harvest equipment food contact surfaces;” and
- There’s no obvious explanation about how the E. coli was transferred to the reservoir.
“The circumstances which lead to produce contamination and foodborne illness outbreak are often situation specific but involve previously identified hazards and routes of contamination,” according to the report. “In this case use of agricultural water contaminated with the outbreak strain of E. coli O157:H7 was the most likely cause of the outbreak.”
The FDA made recommendations to the industry similar to those made in an Environmental Assessment issued after an E. coli outbreak in spring 2018.
All segments of the leafy green industry should review their operations, procedures, policies and practices, and follow regulations in the Produce Safety Rule and other parts of the Food Safety Modernization Act, according to the report.
Specific recommendations include:
- Growers should assure all agricultural water is safe and assess and mitigate risks near water sources;
- Growers/processors should perform a “root cause analysis” when pathogens are found at the farm level or on fresh-cut, ready-to-eat produce;
- All links in the supply chain should ensure traceback from consumer to grower is possible in “real time,” and consumers have harvest date/location information; and
- Industry should adopt technology that allows this traceback.