On Tuesday, the U.S. Centers for Disease Control and Prevention (CDC) issued an update on the multistate outbreak of listeriosis linked to frozen vegetables. Here is what the agency knows so far:

What
There have been 8 reported cases of listeriosis linked to frozen vegetables. The implicated food products were recalled. Recalled items were sold nationwide and in Canada.

How
Epidemiologic and laboratory testing shows that frozen vegetables produced by Pasco, WA’s CRF Frozen Foods is one likely source of the outbreak. The frozen vegetables were sold under a variety of different brand names, including Panda Express, Safeway Kitchens, Walmart's Great Value and Season's Choice .

When
The specific outbreak strains of Listeria in this case actually date back to September 2013. Since March 2016, the CDC has worked with the U.S. Food and Drug Administration and public health officials in the affected states to investigate the outbreak. In late April, CRF Frozen Foods recalled 11 frozen vegetable products because they may have been contaminated with Listeria. In early May, CRF Frozen Foods expanded the initial recall to include all organic and traditional frozen vegetable and fruit products processed in its Pasco, WA facility since May 1, 2014. Approximately 358 consumer products sold under 42 separate brands were recalled.

Who
The outbreak has led to eight hospitalizations. Although two people affected by the outbreak have died, the CDC does not believe that listeriosis was the cause of death for either.

Where
So far, three states have been implicated. The two deaths (reportedly not linked to listeriosis) were victims in Maryland and Washington. The third affected state is California.

What’s next?
Investigations are ongoing to determine if food sources used to manufacture CRF Frozen Foods products could explain some of the illnesses.

In the meantime, the 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.

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