Public Health Notice – Outbreak of E. coli infections linked to romaine lettuce

This notice is being updated to include 10 additional cases that have been reported in the outbreak. There are now a total of 40 cases of E. coli O157 under investigation. There appears to be an ongoing risk of E. coli infections associated with the consumption of romaine lettuce. Individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador are advised to consider consuming other types of lettuce, instead of romaine lettuce, until more is known about the outbreak and the cause of contamination.  

Why should you take note?

The Public Health Agency of Canada is collaborating with provincial public health partners, the Canadian Food Inspection Agency and Health Canada to investigate an outbreak of Escherichia coli O157, commonly called E. coli. The outbreak involves five eastern provinces. Based on the investigation findings to date, exposure to romaine lettuce has been identified as the source of the outbreak, but the cause of contamination has not been identified. The outbreak appears to be ongoing, as illnesses linked to romaine lettuce continue to be reported to the Public Health Agency of Canada. These illnesses indicate that contaminated romaine lettuce may still be on the market (including in restaurants, grocery stores and any establishments that serve food). At this time, the investigation evidence suggests that there continues to be a risk of E. coli infections associated with the consumption of romaine lettuce.

Because of the ongoing risk in eastern Canada, the Public Health Agency of Canada is advising individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador to consider consuming other types of lettuce, instead of romaine lettuce, until more is known about the outbreak and the cause of contamination.

The outbreak investigation is continuing, and this public health notice will be updated on a regular basis as the investigation evolves.

How does lettuce become contaminated with E. coli?

E. coli are bacteria that live naturally in the intestines of cattle, poultry and other animals. A common source of E. coli illness is raw fruits and vegetables that have come in contact with feces from infected animals. Leafy greens, such as lettuce, can become contaminated in the field by soil, contaminated water, animals or improperly composted manure. Lettuce can also be contaminated by bacteria during and after harvest from handling, storing and transporting the produce. Contamination in lettuce is also possible at the grocery store, in the refrigerator, or from counters and cutting boards through cross-contamination with harmful bacteria from raw meat, poultry or seafood. Most E. coli strains are harmless to humans, but some varieties cause illness.

Investigation summary

Currently, there are 40 cases of E. coli O157 illness under investigation in five eastern provinces: Ontario (8), Quebec (13), New Brunswick (5), Nova Scotia (1), and Newfoundland and Labrador (13). Individuals became sick in November and early December 2017. Sixteen individuals have been hospitalized. One individual has died. Individuals who became ill are between the ages of 4 and 85 years of age. The majority of cases (73%) are female.

Most of the individuals who became sick reported eating romaine lettuce before their illnesses occurred. Individuals reported eating romaine lettuce at home, as well as in prepared salads purchased at grocery stores, restaurants and fast food chains. The Canadian Food Inspection Agency is working with public health officials to determine the source of the romaine lettuce that ill individuals were exposed to. At this time, there is no evidence to suggest that provinces in western Canada are affected by this outbreak.

Who is most at risk?

This outbreak strain of E. coli (O157) is one of the strains more likely to cause severe illness.  Pregnant women, those with weakened immune systems, young children and older adults are most at risk for developing serious complications.   

What should you do to protect your health?

It is difficult to know whether a product is contaminated with E. coli because you can’t see, smell or taste it. Romaine lettuce can have a shelf life of up to five weeks; therefore it is possible that contaminated romaine lettuce purchased over the past few weeks may still be in your home. Individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador should consider consuming other types of lettuce, instead of romaine lettuce, until more is known about the outbreak and the cause of contamination.

If you do choose to eat romaine lettuce, the following food handling tips can help to reduce the risk of an E. coli infection, but they will not fully eliminate the risk of illness.

• Wash your hands thoroughly with warm water and soap for at least 20 seconds, before and after handling lettuce.
• Unwashed lettuce, including whole heads of lettuce sold in sealed bags, should be handled and washed using these steps:
  • Discard outer leaves of fresh lettuce.
  • Wash unpackaged lettuce under fresh, cool running water. There is no need to use anything other than water to wash lettuce. Washing it gently with water is as effective as using produce cleansers.
  • Keep rinsing your lettuce until all of the dirt has been washed away.
  • Don’t soak lettuce in a sink full of water. It can become contaminated by bacteria in the sink.
  • Store lettuce in the refrigerator for up to seven days. Discard when leaves become wilted or brown.
  • Use warm water and soap to thoroughly wash all utensils, countertops, cutting boards and storage containers before and after handling lettuce to avoid cross-contamination. 
• Ready-to-eat lettuce products sold in sealed packages and labelled as washed, pre-washed or triple washed do not need to be washed again. These products should also be refrigerated and used before the expiration date.

What are the symptoms?

People infected with E. coli can have a wide range of symptoms. Some do not get sick at all, though they can still spread the infection to others. Others may feel as though they have a bad case of upset stomach. In some cases, individuals become seriously ill and must be hospitalized.

The following symptoms can appear within one to ten days after contact with the bacteria:

• nausea
• vomiting
• headache
• mild fever
• severe stomach cramps
• watery or bloody diarrhea

Most symptoms end within five to ten days. While most people recover completely on their own, some people may have a more serious illness that requires hospital care, or may lead to long-lasting health effects. In rare cases, some individuals may develop life-threatening symptoms, including stroke, kidney failure and seizures, which could result in death.

There is no real treatment for E. coli infections, other than monitoring the illness, providing comfort, and preventing dehydration through proper hydration and nutrition. People who develop complications may need further treatment, like dialysis for kidney failure. You should contact your health care provider if symptoms persist.

What is the Government of Canada doing?

The Government of Canada is committed to food safety. The Public Health Agency of Canada leads the human health investigation into an outbreak and is in regular contact with its federal and provincial partners to monitor the situation and to collaborate on steps to address the outbreak.

Health Canada undertakes food-related health risk assessments to determine whether the presence of a certain substance or microorganism poses a health risk to consumers.

The Canadian Food Inspection Agency conducts food safety investigations into the possible food source of an outbreak.

The Government of Canada will continue to update Canadians as new information related to this investigation becomes available.