In October 2019 Public Health Seattle King County (PHSKC) announced an outbreak of E. coli O157:H7 infections associated with Evergreens restaurants in Seattle. Sixteen people developed symptoms consistent with an E. coli illness after consuming food from six different Evergreens restaurants in King County. Eleven were laboratory confirmed. Genetic testing on isolates from the ten cases indicates that the strains were closely related, suggesting a common source. Illness onsets occurred between November 8-17, 2019. Meal dates occurred between November 5-11, 2019. Three people were hospitalized. There were no deaths.

PHSKC environmental health investigators did onsite investigations at each of the 6 locations. During their field investigations, they did not observe environmental or behavioral risk factors associated with the spread of E. coli. PHSKC did identify four employees who experienced symptoms consistent with an E. coli infection after eating at Evergreens There is no evidence to suggest employees were the source of the outbreak.

Epidemiologic evidence and traceback completed by the US FDA suggest leafy greens as a possible source. Genetic testing completed on isolates obtained from the confirmed cases were closely related. However, they did not match the genetic fingerprint of the strain associated with a national outbreak of E. coli O157:H7 that happened concurrent to the Evergreens outbreak.