Health officials have warned people in the US and Canada not to eat romaine lettuce after an outbreak of food poisoning.
So far 32 illnesses from E. coli poisoning have been reported in the US, with 13 people being hospitalised, but nobody is thought to have died.
Meanwhile in Canada 18 people have been taken ill, with the same strain of bacteria as the cause.
The Centres for Disease Control and Prevention in the US believes the source of the outbreak is romaine lettuce, and has warned businesses and consumers not to use or eat the leaf until the affected batch has been tracked down.
The US Food and Drug Administration's Commissioner Scott Gottlieb told the Associated Press his agency doesn’t have enough information to ask suppliers for a recall.
He added they wanted to get out the warning before people prepared their Thanksgiving meals, so limit the risk of further infections.
E. coli poisoning can cause severe stomach cramps, diarrhea, vomiting, and sometimes fever.
While it can in cases be life-threatening, most people recover within a week.