The CDC and FDA, which have been investigating an outbreak of Listeria tied to frozen vegetable products since March 2016, have declared their investigations over. The outbreak led to the recall of at least 456 different consumer products by CRF Frozen Foods and firms that received CRF-recalled products.
Although the outbreak investigation is over, people can still fall ill with the outbreak illness if they eat contaminated products. The CDC states the following twice in its update: “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.”
9 Outbreak Cases Genetically Confirmed by CDC
According to the CDC release, the agency confirmed nine cases of Listeria linked to the outbreak. Six of those cases occurred in California. Maryland, Washington and Connecticut each reported one case of the outbreak strain of Listeria.
People with confirmed cases ranged from 56 to 91 years old, with a median age of 76. Females accounted for 7 of the 9 outbreak cases, or 78%.
Linking “Cold Cases” to Ongoing Outbreak
The first confirmed case occurred in September 2013. Investigators confirmed the link to the current outbreak by using the CDC 
PulseNet system. Public health agencies perform DNA fingerprinting on bacteria such as E. coli and Listeria collected from ill people. CDC PuleNet manages a national database of these DNA fingerprints. The database assists in identifying outbreak and outbreak victims.
Investigators also identified the five illnesses that occurred in 2015 through a retrospective review of the PulseNet database. No cases identified as outbreak cases occurred during the year 2014. The remaining three cases occurred in the first months of 2016.
3 Fatalities Reported, 1 Attributed to Listeria
All nine cases in this outbreak required hospitalization. Unfortunately, three cases ended in the death of the patient.
When someone with listeria dies, other causes often contribute to that person’s death. This makes determining whether or not the death should be entirely, or in part, attributed to Listeria difficult.
In this outbreak, Listeria was listed as the cause of death in the Connecticut case. For the other two fatalities, which occurred in Maryland and Washington, Listeria infection was not considered as a cause of death.
None of the six California case-patients died.
The CRF Frozen Foods Outbreak Investigation
Investigators first identified this outbreak in March 2016. The Ohio Department of Agriculture collected packages of frozen veggies as part of a routine sampling program. Tests showed the presence of Listeria in True Goodness by Meijer-brand sweet cut corn and frozen organic petite green peas. CRF processed and produced both the peas and the corn.
Further testing showed that the Listeria in the frozen corn was closely genetically related to eight bacterial isolates from case-patients, and the isolate from the frozen peas closely related genetically to one isolate from another ill person. According to the FDA, this “close genetic relationship provides additional evidence that people in this outbreak became ill from eating frozen vegetables produced by CRF Frozen Foods.”
Based on these findings, CRF Frozen Foods ceased production at its Pasco, Washington plant and recalled 11 frozen vegetable products due to potential contamination on April 22, 2016.
After speaking with the FDA and CDC, CRF expanded the recall to include “all of its frozen organic and traditional fruit and vegetable products manufactured or processed in its Pasco facility since May 1, 2014.”
450+ Products Recalled in Connection with Outbreak Investigation
CRF Frozen Foods recalled 358 products sold under 42 brand names, not including downstream products. Companies initiated downstream recalls for at least 98 other products that somehow incorporated product already recalled by CRF.
The full list of CRF Frozen Foods products recalled includes familiar brand name such as Trader Joe’s, Signature Kitchens, O Organic and True Goodness. The FDA also compiled a list of downstream recalls made known by the recalling company to the agency. This list includes recalls by well-known companies including Kroger, Hy-Vee and Pita Pal.
