The Centers for Disease Control and Prevention (CDC) has released a statement that the Listeria monocytogenes outbreak linked to recalled CRF Frozen Foods products is over. Epidemiologic and laboratory evidence indicated that frozen vegetables produced by their facility in Pasco, Washington, and sold under different brand names were a “likely source of illness in this outbreak.”
People could still continue to get sick because the recalled products may be in their home freezers and those who don’t know about the recall could still eat them.
Nine people infected with the outbreak strain of Listeria have been reported in four states since September 13, 2013. All nine people were hospitalized, and three of them died. Listeriosis was considered to be a cause of death for one person in Connecticut. For the two deaths in Maryland and Washington, listeriosis was not considered to be a cause of death.
On April 23, 2016, CRF Frozen Fodos recalled 11 frozen vegetable products because of potential Listeria contamination. The recall was expanded on May 2, 2016 to include all organic and traditional frozen vegetable and fruit products sold under 42 separate brand names. In addition, at least 100 other products prepared by other companies that contained the recalled ingredients were recalled.
Public health investigator used the PulseNet system to identify illnesses that may be part of this outbreak. DNA fingerprinting on Listeria bacteria isolated from ill persons were conducted using pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS).
Listeria positive specimens were collected from September 13, 2013 to May 3, 2016. Three illnesses were reported in 2016. The other six illnesses were found through a retrospective review of the PulseNet database. Ill persons ranged in age from 56 to 91 years, with a median age of 76. Seventy-eight of the ill persons were female.
The outbreak was first identified in March 2016. Four of the nine ill persons, or their caregiver, were interviewed during the investigation of this outbreak. Three of those four people reported buying and eating frozen vegetables in the month before they got sick. Two reported eating Organic by Nature brand, and the third person ate O Organic brand; both are produced by CRF Frozen Foods.
During this same time, the Ohio Department of Agriculture collected packages of frozen vegetable products from a retail store 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 are 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 in this outbreak became ill from eating frozen vegetables produced by CRF Frozen Foods.
In addition, the FDA collected environmental samples from Oregon Potato Company, also located in Pasco, Washington, and isolated Listeria monocytogenes bacteria from these samples. WGS showed that the bacteria found in these environmental samples was closely related genetically to eight isolates from ill people in this particular outbreak. Oregon Potato Company then voluntarily recalled wholesale onion products made in their facility, which led to multiple recalls of products sold at retail under many brand names that contained the recalled onions. That recall was never posted on the FDA web site, but retailers that carried the products posted the recalls.
This investigation is over, but make sure that you don’t have any of the recalled products in your home freezer. If you do, throw it away in a sealed bag. Then clean out your refrigerator and/or freezer with a mild bleach solution to kill any remaining bacteria. Listeria bacteria can grow at refrigerator temperatures and freezing does not kill it. Wash your hands well with soap and water after handling these products.