Last weekend, the U.S. Food and Drug Administration expanded its warning for Texas and New Mexico about the contaminated tomatoes to include other states and Canada, the Canwest News Agency reported Tuesday.

As a result, Subway, McDonald's, and Burger King in Canada have all stopped serving uncooked tomatoes as most of their supplies come from the United States, the report said.

Marc Richard, spokesman for the Canadian Food Inspection Agency, told the news service the agency is closely monitoring the U.S. outbreak, but said no cases have been reported in Canada since it began in April.

He praised the major chains' decision to pull tomatoes for the time being, saying the were practicing "an abundance of caution."

About 140 cases of the Salmonella Saintpaul have been reported in the United States, with at least 23 people requiring hospitalization, the report said.