Thanks to the Marler Clark Epidemiology team for keeping up with foodborne illness outbreaks. Candidly, I could not recall any outbreak ever linked to walnuts. However, look what I found dating back to 2011 in Canada – 14 ill, 10 hospitalized and 1 death.

2011 Outbreak of E. coli O157:H7 Linked to Amira Enterprises Raw Shelled Walnuts, Canada 

On April 4, the Public Health Agency of Canada announced that an outbreak of E. coli O157:H7 had occurred in the provinces of Quebec, Ontario, and New Brunswick. Several people had consumed raw shelled walnuts; walnuts were suspected as the vehicle of infection. The implicated walnuts were distributed by Amira Enterprises of Quebec, Canada, and had been imported from the United States. Products were sold in bulk and packages. Consumers who bought in bulk may not be able to identify the source of the walnuts. The affected products were available for purchase between January 1 and April 4, 2011.

Thanks to www.outbreakdatabase.com.