Romaine lettuce has been linked to an outbreak of E. coli in the US and Canada, health officials say.
At least 32 people have been sickened in the US, with 13 taken to hospital, while another 18 people have been stricken in Canada.
US officials said consumers, restaurants and retailers should throw away all kinds of romaine lettuce.
The latest outbreak follows the deaths of at least five people in the summer linked to romaine lettuce.
However, the latest statement from the US Centers for Disease Control and Prevention (CDC) says this outbreak is not directly related to the cases earlier in 2018, with a slightly different DNA fingerprint for this strain of the illness.
- E. coli bacteria: Friend or foe?
- How should you wash salad and vegetables?
People began to fall ill in early October. An investigation into the outbreak is ongoing.
In Canada, the 18 cases were reported in the provinces of Ontario and Quebec. The infections in the US are spread over 11 states.
In June, five people died and hundreds of people were infected across 35 US states after a romaine lettuce-linked E. coli outbreak.
The illness can cause diarrhoea, vomiting and even kidney failure in severe cases.
Avoiding E. coli infection
Wash hands thoroughly after using the toilet, before and after handling food, and after handling animals
Remove any loose soil before storing vegetables and salads
Wash all vegetables and fruits that will be eaten raw
Store and prepare raw meat and unwashed vegetables away from ready-to-eat foods
Do not prepare raw vegetables with utensils that have also been used for raw meat
Cook all minced meat products, such as burgers and meatballs, thoroughly
People who have been ill should not prepare food for others for at least 48 hours after they have recovered