Risks Associated with Sprouts

The Issue

Sprouts, including mung beans and alfalfa sprouts, have become a common food item in grocery stores, salad bars and Asian dishes across Canada. As the popularity of sprouts increases, so does the potential for sprout-related illnesses. Health Canada is taking action on several fronts to help reduce the risk of illnesses related to sprouts.


Sprouts are the germinating form of seeds and beans. As many as 10% of Canadians eat sprouts on a regular basis. In addition, small amounts of sprouts are now found in some sandwiches, salads and Asian dishes bought at restaurants and delicatessens. This increases the potential exposure of Canadians to sprouts.

Sprouts and Foodborne Illnesses

Worldwide, at least 37 outbreaks of foodborne illnesses have been linked to sprouts between 1973 and 2005. In most instances, the illnesses were caused by either Escherichia coli (E. coli) O157:H7 or Salmonella bacteria.

Between 1996 and 2005, raw alfalfa sprouts and mung bean sprouts contaminated with Salmonella have been linked to a number of outbreaks in British Columbia, Quebec, Ontario, Saskatchewan and Alberta, as well as in the United States.

The largest outbreak linked to sprouts took place in Japan in 1996, when 6,000 people got sick and 17 died after eating radish sprouts contaminated with E. coli O157:H7. This type of bacteria was also implicated in outbreaks involving sprouted seeds in several U.S. states between 1997 and 2004.

How Sprouts Can Become Contaminated

Scientists believe that the most likely source of contamination is the seeds that are used to grow the sprouts. Seeds may become contaminated by animal manure in the field or during storage, and the conditions required to grow sprouts (e.g, warmth and humidity) are ideal for the rapid growth of bacteria. Poor hygienic practices in the production of sprouts have also caused some sprout-related outbreaks of foodborne illness in the past.

Most sprouts, including alfalfa sprouts, can only be eaten raw. This means they are not exposed to temperatures high enough to kill bacteria that may be present. Some sprouts, such as mung bean sprouts, can also be eaten cooked. To ensure that bacteria are destroyed, these sprouts should be cooked thoroughly. A recent outbreak of salmonellosis in Ontario in 2005 was linked to the consumption of raw and lightly-cooked mung bean sprouts, such as those found in some stir-fry dishes.

The Risks of Eating Raw Sprouts

Anyone who eats raw sprouts or lightly cooked mung bean sprouts, is at risk for exposure to E. coli O157:H7 or Salmonella bacteria. However, the risk of serious health effects is greater for young children, seniors and people with weak immune systems.

The symptoms of E. coli O157:H7 infection can include stomach cramps, vomiting, fever and bloody diarrhea. Symptoms can occur within two to 10 days of eating contaminated food. A small percentage of people can develop a serious condition called haemolytic uremic syndrome, and may need blood transfusions and kidney dialysis. Severe cases could cause permanent kidney damage or even death.

People infected with Salmonella bacteria may experience fever, headache, stomach cramps, diarrhea, nausea and vomiting. These symptoms usually occur 12 to 36 hours after eating contaminated food, and can last for seven days. Severe cases may require hospitalization.

If you experience any of the symptoms of E. coli or Salmonella infection, you should contact your doctor immediately.

Minimizing Your Risk

If you belong to one of the groups at high risk for serious health effects from foodborne illness (young children, seniors, or people with weak immune systems), avoid eating raw sprouts, especially alfalfa sprouts and mung bean sprouts. Be sure to check for the presence of sprouts in salads, sandwiches and soups you buy in restaurants and delicatessens.

In addition, you should also avoid eating cooked mung bean sprouts found in stir-fries or soups, unless you can determine that the sprouts have been thoroughly cooked.

If you are a healthy adult and wish to eat sprouts, you can minimize your risk by taking the following precautions:

* If possible, buy sprouts that have been stored at refrigerated temperatures. Select crisp-looking sprouts. Avoid sprouts that look dark or smell musty.
* If buying bean sprouts in bulk display, use tongs or a glove to place the sprouts into a plastic bag.
* Refrigerate the sprouts immediately when you get home. Your refrigerator temperature should be at or below 4C (40F). Use a thermometer to check.
* Respect the best-before date on prepackaged sprouts. Throw away any unused sprouts after a few days, or as soon as they lose their crispness.
* If you choose to eat mung bean sprouts, make sure they have been thoroughly cooked to kill any bacteria that may be present. Reduce your risk of foodborne illness by avoiding raw or lightly-cooked mung bean sprouts.

The Government of Canada's Role

Health Canada is working with industry representatives, public health officials, the Canadian Food Inspection Agency and other stakeholders to implement safer growing methods for sprouts. Some of the steps taken to date include:

* The recent finalization of a Food Directorate Policy on Managing Health Risk Associated with the Consumption of Sprouted Seeds and Beans (December 2006).
* The development of Guidance for Industry on Sampling and Testing Sprouts and Spent Irrigation Water as part of the Food Directorate Policy
* The development of a Code of Practice for the safe growing and distribution of sprouted seeds and beans. This Code emphasizes the use of Good Manufacturing Practices for sprouts.
* The regular inspection by the Canadian Food Inspection Agency (CFIA) of sprout growing establishments to ensure good hygienic practices.
* Health Canada and CFIA are currently developing additional educational material for consumers and the sprout growing industry.

Health Canada also warns consumers about the risks of eating sprouts and advises the public on steps that can be taken to reduce the risk of contracting sprout-related illnesses.

For additional articles on health and safety issues go to the It's Your Health Web site. You can also call toll free at 1-866-225-0709 or TTY at 1-800-267-1245*.

Her Majesty the Queen in Right of Canada,
represented by the Minister of Health
January 2007