CDC Closes Frozen Vegetable Listeriosis Investigation
The DeKalb County, Georgia-headquartered Centers for Disease Control and Prevention (CDC) on July 15 issued a final update on its probe into a multi-state outbreak of Listeria monocytogenes infections traced to consumption of frozen vegetables packed by Pasco, Oregon-based CRF Frozen Foods. The bacterial infection, linked to nine hospitalizations and three deaths, prompted a massive recall of hundreds of products distributed under more than 40 brand names and private labels including Kroger, Safeway Kitchens and Trader Joe’s in the USA, Canada and beyond.
“This outbreak investigation is over. However, people could continue to get sick because recalled products may still be in freezers and people who don’t know about the recalls could eat them. Retailers should not sell and consumers should not eat recalled products,” declared the CDC in an advisory posting at its website.
Findings from the CDC, a federal agency that is the leading national public health institute in the United States, were summarized as follows:
Epidemiologic and laboratory evidence indicated that frozen vegetables produced by CRF Frozen Foods of Pasco, Washington, and sold under various brand names were a likely source of illnesses in this outbreak, which was identified in March of 2016.
State and local health departments attempted to interview those who were taken ill, a family member or a caregiver about the foods the sick person may have eaten in the month before the illness began. Four of nine ill people, or their caregiver, were interviewed using a questionnaire that asked about a variety of foods. Three of them reported buying and eating frozen vegetables in the month before illness began, and two specifically identified Organic by Nature brand frozen vegetables. The third ill person reported eating O Organic brand frozen vegetables. Both Organic by Nature and O Organic frozen vegetables are produced by CRF Frozen Foods.
During the same time period, as part of a routine product sampling program, the Ohio Department of Agriculture collected packages of frozen vegetables from a retail location and isolated Listeria from True Goodness by Meijer brand frozen organic white sweet cut corn and from True Goodness by Meijer brand frozen organic petite green peas. Both products were produced by CRF Frozen Foods.
Whole genome sequencing (WGS) showed that the Listeria isolate from the frozen corn was closely related genetically to eight bacterial isolates from ill people, and the Listeria isolate from the frozen peas was closely related genetically to one isolate from an ill person. This close genetic relationship provides additional evidence that some people stricken in this outbreak were sickened from eating frozen vegetables produced by CRF Frozen Foods.
Also, the US Food and Drug Administration (FDA) collected environmental samples from Oregon Potato Company, based in Pasco, Washington, and isolated Listeria from these samples. WGS showed that the Listeria found in these environmental samples was closely related genetically to eight isolates from ill people in the outbreak. Based on this information, Oregon Potato Company voluntarily recalled wholesale onion products made in its facility, which led to multiple recalls of products sold at retail stores under many brand names that contained recalled onions.
On April 23, 2016, CRF Frozen Foods recalled 11 frozen vegetable products because it was believed they might have been contaminated with Listeria. On May 2, 2016, CRF expanded the initial recall to include all organic and traditional frozen vegetable and fruit products processed in its Pasco facility since May 1, 2014. More than 350 consumer products sold under 42 separate brands were recalled, as well as at least 100 additional products from other companies that contained recalled ingredients from CRF Frozen Foods.
State health departments collected recalled products from ill people in California and Idaho and isolated an outbreak strain of Listeria in these samples. Recalled items were sold under various brand names nationwide and in Canada. A full list of recalled products is available on the FoodSafety.gov website.
CDC recommends that consumers do not eat, and restaurants and retailers do not serve or sell, recalled organic and traditional frozen vegetables and fruit products and recalled products that contain these items.
Meanwhile, the CRF Pasco plant where the frozen vegetables were produced remains closed. Reportedly the privately held company, a unit of R.D. Offutt Co., is redesigning the facility with state-of-the-art equipment as well as bolstering food processing safety procedures.