The romaine lettuce traceback investigation has narrowed down the source to the farm level, which further narrows the growing areas to Monterey, San Benito, and Santa Barbara counties in California. Consumers and retailers should avoid eating, selling, and serving romaine lettuce that originated in these areas.

The traceback investigation teams—including the U.S. Food and Drug Administration’s Produce Safety Network,  the U.S. Centers for Disease Control and Prevention, the California Department of Public Health, and the California Department of Food and Agriculture—analyzed samples of romaine lettuce, soil, water, sediment, and animal droppings gathered from the farms implicated thus far in the teams’ traceback efforts. Most samples tested negative for the outbreak strain. Other samples are still being tested.

One sediment sample from an agricultural water reservoir at the Adams Bros. Farming ranch in Santa Barbara County did test positive for the Escherichia coli O157:H7 outbreak strain that caused the outbreak. The strain found in the sample matched the strain collected from ill individuals in this outbreak. Adams Bros. Farming harvests broccoli, cauliflower, and celery in addition to lettuce—romaine, red, green leaf, and iceberg.

FDA says that Adams Bros. Farming has not shipped any romaine lettuce since November 20, 2018. Experts are working with the farm to determine how contamination occurred and what corrective actions need to be taken before their next growing season. Adams Bros. Farming is fully cooperating with health officials and the ranch has committed to recalling products that may have come into contact with water from the water reservoir where the outbreak strain was found.

Despite pinpointing this farm, FDA says that the positive sample finding still does not explain all the illnesses in the outbreak. The FDA’s traceback activities of romaine lettuce will continue as FDA works to determine what commonalities this farm may have with other farms and areas that are being assessed as part of the investigation.

At last count, FDA says that this outbreak has resulted in 59 illnesses in 16 states, and 23 people had to be hospitalized. There have been no deaths reported in relation to this outbreak.

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