In an update yesterday, the US Centers for Disease Control and Prevention (CDC) said seven more infections have been reported in a multistate Escherichia coli O157:H7 outbreak that appears to be linked to leafy greens, but so far the investigation hasn't pointed to a specific type to guide any advice about foods to avoid.
In a related development, Canadian officials said its related E coli outbreak, linked to romaine lettuce, appears to be over.
Two more affected states
The latest confirmed illnesses raise the outbreak total to 24 cases, and 2 new states have reported cases—Maryland and New Jersey—raising the number of affected states to 15. Of 18 cases with available information, 9 patients were hospitalized, including 1 from California who died. Two people developed hemolytic uremic syndrome, a potentially fatal kidney complication.
The most recent illness onset was Dec 12. The CDC said leafy greens typically have a short shelf-life, and since the last illness began about 1 month ago, it's likely that contaminated leafy greens connected to the outbreak are no longer available for sale.
The CDC has said whole-genome sequencing suggests that the US outbreak is related to a similar recent outbreak in eastern Canada that investigators there linked to romaine lettuce.
State and local public health authorities are still interviewing sick patients to see what they ate the week before they got sick, the CDC said. Of 13 people interviewed, all reported eating leafy greens. Of those, 5 (56%) of 9 patients remembered eating romaine, a percentage that wasn't significantly higher than results from a survey of healthy people, which showed 46% had eaten romaine the week before.
"Based on this information, U.S. health officials concluded that ill people in this outbreak were not more likely than healthy people to have eaten romaine lettuce," the CDC said, adding that patients ate different romaine types and brands and that no common supplier, distributor, or retailer has been identified. Officials are continuing their investigation.
Experts urge caution; lawmakers press for answers
Some food safety experts, however, say that the lack of a stronger federal warning about a possible risk from romaine lettuce could give the pubic a false sense of security.
James Rogers, PhD, director of food safety research and testing at Consumer Reports, said yesterday in a report from the magazine that without knowing what exactly caused the outbreak, the CDC's stance could give consumers a false sense of security. For example, if processing equipment was contaminated, new product could trigger future infections.
Also, some lawmakers are questioning why the CDC didn't alert consumers sooner and give them information on how to protect their health.
Rep. Rosa DeLauro (D-Conn.) in a Jan 8 letter to the CDC asked the agency to explain why it waited so long to confirm the outbreak and if it has collaborated with Canadian officials on the investigation. DeLauro is a member of a House subcommittee that investigates health issues, including foodborne illness outbreaks.
Rep Louise Slaughter (D-N.Y.), in comments to Consumer Reports, questioned a lack of timely information from the Food and Drug Administration (FDA) as well as the CDC and called on the FDA to take all necessary steps to protect public health. Slaughter is a microbiologist.
In a statement yesterday, its first regarding the outbreak, the FDA said its outbreak investigation team is working with the CDC, as well as with state and local partners, to identify a common food or point where the food may have become contaminated.
"At this point, we have not identified a common or single point of origin for the food that made people ill," the FDA said. "We want to make sure the information we provide is accurate and when we have information that consumers can use—such as any foods to avoid—we will share it immediately."
Canada's outbreak appears over
In an update yesterday, the Public Health Agency of Canada (PHAC) said the E coli outbreak in Canada appears to be over, and it is no longer advising people in affected provinces to avoid eating romaine lettuce.
The PHAC said the Canadian Food Inspection Agency has completed its food safety investigation, and all samples of romaine lettuce were negative for E coli O157:H7.
As of yesterday, 42 cases had been reported to the PHAC, 1 more than the PHAC's previous update on Dec 28. The sick patients are from five eastern provinces: Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador. Seventeen people were hospitalized, and one death was reported.
Most of the people reported eating romaine lettuce from a variety of sources before they became ill, including at home and in prepared salads bought at grocery stores, restaurants, and fast-food chains.
Jan 10 CDC update
Jan 10 Consumer Reports story
Jan 8 DeLauro letter
Jan 10 FDA statement
Jan 10 PHAC update