Listeria linked to frozen vegetables sickens 8 in 3 states

A three-state Listeria outbreak linked to a Washington company's frozen vegetables has sickened eight people, with two deaths reported, and led to a recall of all vegetables and fruits processed by the company, the US Centers for Disease Control and Prevention (CDC) said yesterday.

Two of the Listeria monocytogenes cases were detected this year, the most recent one on March 28. Using PulseNet, the national foodborne pathogen subtyping network, investigators identified six other illnesses matching the outbreak strain from as far back as September 2013, the CDC said. Six patients are from California, while Maryland and Washington each have a case.

All patients hospitalized

All of the patients were hospitalized, and the ones from Maryland and Washington died, though listeriosis wasn't considered the cause of death for either person, according to the CDC. All were adults ages 56 to 86.

Listeriosis mainly affects older adults, pregnant women, newborns, and people with compromised immune systems, with symptoms that include fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions. Infections in pregnant woman can lead to miscarriage, stillbirth, or premature delivery.

Symptoms can begin anytime from 3 to 70 days after infection.

Interviews, tests implicate frozen vegetables

Epidemiologic and lab evidence suggests the likely source of the outbreak is frozen vegetables produced by CRF Frozen Foods, based in Pasco, Wash., and sold under different brands, the CDC said.

Two patients reported buying and eating the same Organic Nature brand of frozen vegetables in the month before they got sick, and routine product sampling by the Ohio Department of Agriculture found Listeria in frozen organic sweet corn and green peas under the Meijer grocery store chain's True Goodness brand, also produced by CRF Frozen Foods.

Whole-genome sequencing showed that the Listeria strain in the frozen corn was closely related to seven Listeria isolates from sick patients, and Listeria from the frozen peas was closely related to an isolate from one of the people.

Recall includes 358 products, 42 brands

CRF recalled 11 of its frozen vegetable products on Apr 23, then expanded it on May 2 to include all of its organic and traditional frozen vegetable and fruit products processed in its Pasco facility since May 1, 2014. The recalled products, packaged in plastic bags, are distributed nationally and in four Canadian provinces: British Columbia, Alberta, Manitoba, and Saskatchewan.

In its expanded recall notice yesterday, CRF Frozen Foods said the recall covers 358 consumer products sold under 42 separate brands. It said that, after the initial recall on Apr 25, it suspended operations at the Pasco facility to allow a thorough review.

The CDC said the ongoing investigation is complex and that efforts are under way to determine if contaminated food sources could explain some of the infections.

See also:

May 3 CDC outbreak announcement

May 2 Food and Drug Administration expanded recall notice

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