Romaine lettuce - E. coli - CLOSED

February 9, 2018 – Final Update - Outbreak over

This is the final update for this outbreak. The outbreak investigation has been closed. No additional cases have been reported since the last update. The United States Centers for Disease Control and Prevention has also indicated that their outbreak appears to be over.

Why should you take note?

The Public Health Agency of Canada collaborated 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 involved five eastern provinces. Based on the investigation findings during the outbreak, exposure to romaine lettuce was identified as the source of the outbreak, but the cause of contamination was not identified. No individuals have had illness onset dates beyond December 12, 2017. As a result, the outbreak appears to be over, and the investigation has been closed. The risk to Canadians is low.

Although the outbreak appears to be over, the Public Health Agency of Canada advises Canadians to always follow safe food handling tips for preparing lettuce. Individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador are no longer advised to consider consuming other types of lettuce, instead of romaine lettuce.

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

In total, there were 42 cases of E. coli O157 illness reported in five eastern provinces: Ontario (8), Quebec (15), New Brunswick (5), Nova Scotia (1), and Newfoundland and Labrador (13). Individuals became sick in November and early December 2017. Seventeen individuals were hospitalized. One individual died. Individuals who became ill were between the ages of 3 and 85 years of age. The majority of cases (74%) were female. There was no evidence to suggest that provinces in western Canada were affected by this outbreak.

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 worked with public health officials to determine the source of the romaine lettuce that ill individuals were exposed to. As part of the food safety investigation into the source of contamination, the Canadian Food Inspection Agency tested various romaine lettuce samples for the presence of E. coli. All food samples tested negative and no source of contamination was identified.

On December 28, 2017, the United States Centers for Disease Control and Prevention (US CDC) issued a media statement regarding a multistate outbreak of E. coli infections that were genetically related to the outbreak in Canada. On January 25, 2018, the US CDC indicated that their outbreak appears to be over.

Who is most at risk?

Although anyone can get an E. coli infection, pregnant women, those with weakened immune systems, young children and older adults are most at risk for developing serious complications. This is especially true for this outbreak strain of E. coli (O157) which is more likely to cause severe illness than other E. coli strains in Canada.

Most people with an E. coli infection will become ill for a few days and then recover fully. Some E. coli infections can be life threatening, though this is rare.

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. The best way to protect your health is to practice safe food handling on a daily basis. The following food safety tips for lettuce 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 if new information related to this investigation becomes available.

Additional information

• Leafy Greens Fact Sheet
• E. coli Fact Sheet
• General Food Safety Tips
• Befoodsafe.ca
• Recalls and safety alerts mobile application

Media Contact

Public Health Agency of Canada
Media Relations
(613) 957-2983

Public Inquiries
Call toll-free: 1-866-225-0709
Email: info@hc-sc.gc.ca

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Background and previous updates