Health officials have discovered the first Canadian case linked to a massive salmonella outbreak in the United States that has sickened more than 900 people.

The Public Health Agency of Canada announced Thursday that an unidentified person from Ontario who recently travelled to the U.S. has tested positive for Salmonella Saintpaul.

"From the information that we have right now it looks like this person acquired their infection when they were travelling in the U.S," said Andrea Ellis, an epidemiologist with the agency's centre for foodborne, environmental and zoonotic (transmitted to humans from lower vertebrates) diseases.

"Given the number of cases in the U.S. and the number of [Canadian] travellers to the U.S., we certainly would expect to see some cases like that."

A form of food poisoning, the bacterial malady has affected 922 people across 40 states and the District of Columbia, according to the U.S. Centres for Disease Control.

Ellis would not reveal where in the U.S. the Canadian person may have contracted the illness, but said "there continues to be no evidence that we have this pathogen originating here in Canada."

The agency has notified the CDC, and is asking Canadian health officials to watch for illnesses caused by the salmonella strain.

Salmonella, which normally lives in the intestinal tract of animals and birds, is transmitted to people through food contaminated with animal feces.

The U.S. government recently expanded its hunt for the source of the salmonella outbreak, which began in April, turning its focus beyond tomatoes to other fresh produce. Investigators are baffled by the fact that cases continued to be reported two months after the outbreak began, fearing that the pathogenic food could still be on the market.

They are now said to be looking at other foods commonly served with tomatoes, such as the ingredients used in fresh salsa.

Pressure is increasing on the U.S. Food and Drug Administration to solve the case, with the tomato industry suffering millions of dollars in losses. The industry is pushing the U.S. Congress to investigate how the FDA has handled the outbreak.

With files from the Canadian Press