E coli probe prompts CDC warning to avoid all romaine

The US Centers for Disease Control and Prevention (CDC) today warned consumers not to eat any romaine lettuce and for retailers and restaurants not to sell or serve it, as US and Canadian officials investigate an Escherichia coli O157:H7 outbreak.

The warning applies to all types of romaine, including whole heads, hearts of romaine, bags and boxes of precut lettuce, and any salad mix that contains romaine. It urges people to throw the product away if it's not clear if a salad mix contains romaine and to sanitize refrigerator drawers or shelves where romaine was stored.

50 people sick in US, Canada

So far 32 illnesses have been confirmed in 11 states, and the Public Health Agency of Canada (PHAC) has identified 18 people in Ontario and Quebec infected with the same E coli fingerprint.

California (10) and Michigan (7) have reported the most cases, with smaller numbers reported by Connecticut, Illinois, Massachusetts, Maryland, New Hampshire, New Jersey, New York, Ohio, and Wisconsin.

Regarding the US cases, the CDC said illness onsets range from Oct 8 to Oct 31, and 13 people have been hospitalized, including one with hemolytic uremic syndrome, a potentially fatal kidney complication. No deaths have been reported.

The outbreak isn't related to an outbreak earlier this year that was traced to romaine from growing regions in Arizona.

Today's warning is broad, because so far no common grower, supplier, distributor, or brand has been identified in the investigation.

Interviews with sick patients found that 11 of 14 (79%) had eaten romaine before they got sick, compared with 47% of healthy people who were surveyed. Those who were sick reported eating different types of romaine in restaurants and in their homes.

Strain similar to 2017 leafy greens outbreak

The US Food and Drug Administration (FDA) said genetic analysis of the E coli outbreak strain suggests that it is similar to one implicated in an outbreak that involved leafy greens in the fall of 2017 with related illnesses in Canada. In the United States, the earlier outbreak was linked to 25 cases from 15 states.

Despite an extensive investigation, health officials never identified a common supplier, distributor, or retailer in the 2017 outbreak. Though Canadian investigators identified romaine as the source of the outbreak, US counterparts couldn't identify a specific type of leafy green as the likely source.

See also:

Nov 20 CDC food safety alert

Nov 20 FDA announcement

Nov 2 CIDRAP News story "FDA issues final report on E coli in Arizona-grown romaine"

Jan 11 CIDRAP News story "CDC E coli probe notes 7 more cases, points to leafy greens"

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