The US Food and Drug Administration (FDA) has declined to identify the source of E. coli O157:H7-contaminated romaine lettuce that sickened 89 people across 15 states in November 2024.

Seven of the outbreak victims developed hemolytic uremic syndrome (HUS), and one person died. Thirty-six individuals were hospitalized.

Outbreak cases were reported from Arkansas (2), Colorado (1), Illinois (7), Indiana (8), Kansas (1), Kentucky (1), Missouri (50), Montana (1), North Dakota (2), Nebraska (3), Ohio (8), Pennsylvania (1), South Dakota (1), Tennessee (1), and Wisconsin (2).

Information about the outbreak investigation was obtained from the FDA in response to a Freedom of Information Act (FOIA) request filed by eFoodAlert.

The US Centers for Disease Control and Prevention (CDC) identified seven subclusters in the multistate outbreak, including events linked to a Missouri-based caterer, and Ohio school, an Indiana restaurant, an Illinois restaurant, and an Illinois event catered by a different Missouri-based caterer.

Ninety-five percent (95%) of victims who responded to questionnaires reported consuming leafy greens prior to illness. Romaine lettuce was consumed by 88% of the outbreak victims who were able to remember the exact type of leafy green consumed.

The FDA was notified of the outbreak by the US Centers for Disease Control and Prevention on November 25, 2024. Traceback investigations by the FDA ultimately identified a single processor and a single grower as the source of Romaine lettuce supplied to all of the events that formed part of the outbreak.

What FDA found

On January 15, 2025, the FDA’s Coordinated Outbreak Response and Evaluation (CORE) team supplied the following traceback summary to the CDC:

A traceback investigation was initiated in response to a E. coli O157 outbreak with leafy greens as the suspected vehicle. Each case included in the traceback investigation reported consumption of leafy greens prior to illness onset. Based on information available at the points of service (POS), the traceback focused on iceberg and romaine lettuce. The investigation consisted of [redacted] traceback legs representing twenty-eight cases and [redacted] POS. The [redacted] traceback legs identified [redacted] distribution centers, [redacted] broker, [redacted] processors, [redacted] grower, and [redacted] ranch. The traceback investigation determined that a sole processor sourced romaine lettuce from [redacted] grower that would have been available at all points of service during the timeframe of interest. Additionally, romaine lettuce supplied to [redacted] POS was traced back to a common ranch and lot. Through analysis of records, [redacted] lot of romaine lettuce were implicated, resulting in confirmation of romaine lettuce as the vehicle.

The following traceback diagram included in the full CORE report illustrates the supply chain involved in the outbreak.

During the course of its investigtion, the FDA collected a total of twelve (12) environmental and water samples, but did not recover the outbreak strain from any of them.

The CORE report does not indicate whether the samples were collected at the grower or at the processor of the romaine lettuce.

Information withheld

The FOIA request filed by eFoodAlert sought “complete CORE investigation report and any documents related to this outbreak investigation, including Establishment Inspection Report(s), FDA Form 483(s), if issued, results of lab analyses, correspondence between FDA and CDC relating to this investigation.”

We received ONLY the CORE investigation Executive Summary and two emails.

We did NOT receive the requested results of lab analyses.

We did NOT receive a copy of any Establishment Inspection Report (either for the grower or the processor), which would have provided the identity of the establishment(s).

According to the CORE report, no [adverse] observations were noted (ie., no FDA Form 483 issued).

The CDC never posted a public notice for this outbreak.

The FDA chose not to release the name of the grower or the processor because “…there was no product remaining in commerce.”

Why this matters

The victims of this outbreak have a right to know the source of the product that made them ill, and have the right to seek compensation.

The restaurants and caterers who purchased the produce deserve to know the source of the contaminated romaine lettuce so that the can choose to use different suppliers in future.

Finally, deterrence is—or should be—a weapon in the food safety arsenal. If a grower, processor, or manufacturer of any food product knows that they will be identified by name in the event that their product is the source of a foodborne disease outbreak, they will be more likely to take steps to avoid supplying contaminated product to the public.

Interested in learning more about food safety and the history of foodborne disease outbreaks and investigations?

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