Dr. Eilish Cleary says all cases of E. coli 0157 included in a case study had been exposed to romaine lettuce at Jungle Jim's restaurant in Miramichi.
There were 13 confirmed cases of people with E. coli 0157, the same strain found during the Walkerton, Ont., water tragedy in 2000 that killed seven people.
No one in New Brunswick developed serious complications.
During the investigation, the Public Health Agency of Canada became aware of similar cases in Quebec and California, which helped point to romaine lettuce as the source of the illnesses.
Cleary says the lettuce is no longer in the marketplace and the investigation has been closed.