CDC, FDA along with their local and state public health and regulatory partners investigated a multistate outbreak of E. coli O157:H7 infections associated with organic walnut pieces and halves produced by Gibson Farms, Inc. A total of 13 outbreak associated cases were identified. Seven people were hospitalized. No one died. Two patients developed hemolytic uremic syndrome (HUS). Ill cases lived in Washington and California. Dates of illness onset ranged from February 1, 2024 to April 4, 2024.

Walnuts halves and pieces were sold in bulk bins. Expiration dates ranged between May 21, 2025 and June 7, 2025. They were distributed to natural food and co-op stores in AK, AR, AZ, CA, CO, HI, ID, KS, LA, MT, NE, NM, NV, OR, SD, TX, UT, WA and WY. Lot codes were 3325-043 and 3341-501.

The outbreak was declared over on June 25, 2024.