The Centers for Disease Control and Prevention and the U.S. Food and Drug Administration are investigating an outbreak of E. coli potentially linked to organic walnuts sold in food co-ops or natural food stores.

To date, the CDC says officials have reported 12 illnesses and seven hospitalizations in two states – California and Washington – however the true count of illnesses could be much higher than what officials have confirmed and may not be limited to two states, notes food safety attorney Bill Marler.

Infections in the two states have been linked to organic walnut halves and pieces sold from Gibson Farms, Inc. of Hollister, California in bulk bins at natural food and co-op stores, according to the FDA.

So far, state and local public health officials have interviewed 10 people who have gotten sick and all reported eating walnuts – almost all said they had bought organic walnuts from bulk bins in food co-ops or natural food stores, the FDA says.

E. coli outbreak:Walnuts sold in at least 19 states linked to illnesses in California and Washington

Which walnuts are affected by the recall?

If you bought organic walnut halves and pieces from bulk containers, see if yours might be part of the recall. Here's what to check:

• The walnuts were shipped to distributors between the dates of October 1, 2023, to April 24, 2024,
• The expiration dates are from May 21, 2025 to June 7, 2025.
• The walnuts' lot codes are 3325-043 and 3341-501.

You can ask the store where you purchased them if it had sold any recalled walnuts. You can also check the FDA's list of stores where walnuts were distributed.

Some stores may have repackaged bulk walnut halves and pieces into plastic clamshells or bags, officials said. If you can’t tell if it’s part of the recall, it’s safer not to eat them.

Wash any surfaces or items that may have touched the walnuts using hot soapy water or a dishwasher.

Map of where the walnuts were distributed

The walnuts were distributed beyond California and Washington to 17 other states: Alaska, Arkansas, Arizona, Colorado, Hawaii, Idaho, Kansas, Louisiana, Montana, Nebraska, New Mexico, Nevada, Oregon, South Dakota, Texas, Utah and Wyoming.

The FDA is working to determine the source of contamination and whether other products, states and retailers are affected.

Map of where people are reporting illnesses due to the walnuts

Six people each in California and Washington have reported illnesses from eating the potentially contaminated walnuts, according to the CDC. There have also been seven reported hospitalizations.

What is E. coli? What are the symptoms?

Most Escherichia coli (E. coli) bacteria reside harmlessly in the intestines of people and animals. But some can cause mild to life-threatening gastrointestinal illnesses if consumed, the CDC says.

The types of E. coli that may cause diarrhea usually spread through food or water contaminated with feces contact with animals or people. For instance, food handlers can spread infection when they do not use proper hand washing hygiene after using the restroom. Animals such as cattle may also spread E. coli to food and food crops.

E. coli infections can cause severe stomach cramps, diarrhea (often bloody) and vomiting for around five to seven days; infections typically occur three to four days after consuming the germ, according to the CDC.

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Gabe Hauari is a national trending news reporter at USA TODAY. You can follow him on X @GabeHauari or email him at [email protected].