The Public Health Agency of Canada is investigating an E. coli outbreak in three provinces linked to romaine lettuce.

In November, a total of 21 people in Quebec, New Brunswick and Newfoundland and Labrador fell ill with E. coli infections. Ten have been hospitalized. Many of these individuals reported eating romaine lettuce before getting sick.

The Canadian Food Inspection Agency is currently working to determine the source of the lettuce. No product recalls have been issued yet in association with the outbreak.

Escherichia coli O157, commonly referred to as E. coli, is a bacteria that lives in the intestines of many animals. Human E. coli infections are often the result of consuming raw fruits or vegetables that have been contaminated by an infected animal’s feces.

While infected individuals may sometimes exhibit no symptoms, others may experience an upset stomach, nausea, vomiting, headache, stomach cramps and mild fever. Although there is no specific treatment for E. coli infections, most infected individuals fully recover within a few days. Pregnant women, young children, people with weakened immune systems and older adults, however, are at risk of developing more severe complications.

To avoid becoming ill, the Public Health Agency of Canada recommends following safe food handling practices when handling lettuce, such as discarding outer leaves and thoroughly washing your lettuce under cool, running water.