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Salmonella

Salmonella are a group of bacteria that is commonly found in the intestines of animals and birds. The bacteria can be transmitted to people when they eat foods contaminated with animal feces. Often, contaminated foods are of animal origin, such as beef, poultry, milk or eggs; however, all foods, including fruits and vegetables, can become contaminated.

People who eat food contaminated by Salmonella can become ill with salmonellosis. Symptoms of salmonellosis can include diarrhea, vomiting, stomach cramps and fever.

Causes

What causes salmonellosis? How is it spread?

Eating contaminated foods is the most common cause of infection with Salmonella bacteria. Contaminated foods could include raw or under cooked eggs or egg products, meat, poultry, raw fruit and vegetables.

You can also be exposed to Salmonella bacteria by not thoroughly cleaning surfaces that have been used to prepare raw meat and other foods in the kitchen, or if you have not properly washed fresh fruits and vegetables before eating them. Food handlers who have not thoroughly washed their hands after handling raw meat or after using the washroom can also contaminate food.

Salmonella can also be found on some pets. Exotic pets, such as snakes, turtles and reptiles, and dogs and cats may carry the bacteria even when healthy. Foods for these pets can also be contaminated with Salmonella bacteria. You can become infected if you do not wash your hands after touching your pets.

If you are infected with the bacteria you may not get sick or show symptoms, but you can carry the bacteria and spread the infection to others.

Symptoms

What are the symptoms of illness caused by Salmonella?

Like other foodborne illnesses, the symptoms of salmonellosis mainly involve the gut.

Symptoms include sudden onset of:

  • diarrhea
  • fever
  • abdominal cramps
  • nausea, and
  • vomiting

How long do the symptoms last?

Salmonellosis symptoms generally occur within 6 to 72 hours after ingesting the bacteria in food, water or other environmental sources, and last 4 to 7 days.

How long are people infectious?

People who are infected with Salmonella bacteria can be infectious from several days to several weeks. However, some people can become infected with the bacteria and not get sick or show symptoms. Even though you don’t show symptoms, it is still possible to carry the bacteria and spread the infection to others.

Risks

Are there certain foods that increase the risk of getting salmonellosis?

Raw meat, poultry and eggs that are contaminated with Salmonella and have not been cooked properly are the most common sources of illness. The following foods have also been associated with salmonellosis:

  • Unpasteurized dairy products, such as raw milk and raw cheese, and cream-filled desserts and toppings
  • Raw fruit and vegetables (especially sprouts and cantaloupes) and their juices
  • Homemade products such as salad dressings, hollandaise sauce, mayonnaise, ice cream, cookie dough, tiramisu, and frostings

Are certain people more likely than others to get sick from Salmonella?

Some people are more susceptible to infection than others. Seniors and those with weakened immune systems may be unable to fight off the infection, and can get sick more easily than others. These people are also at a higher risk of serious illness from salmonellosis.

Is Salmonella dangerous? Is it more dangerous for certain people?

Most people who become ill from Salmonella bacteria will recover fully after a few days.

In severe cases, salmonellosis can cause serious illness and sometimes death. Seniors and those with weakened immune systems are at higher risk of serious illness. An example of severe illness could be septicaemia (also known as blood poisoning).

In rare cases, severe complications can occur. Some people may experience chronic symptoms, such as reactive arthritis (Reiter's Syndrome) three to four weeks later.

Treatment

How are people diagnosed and treated for Salmonella infection?

There are many different illnesses that cause the same symptoms as salmonellosis. The only way to diagnose it is through laboratory tests on the stools of infected people. Once Salmonella has been identified, further testing can determine the type of Salmonella and the appropriate treatment.

Treatment for those infected with Salmonella should include drinking plenty of liquids to replace the body fluids lost through diarrhea and vomiting. This is particularly important for seniors, children and those with weakened immune systems. In severe cases, patients may need to be given fluids intravenously.

In rare cases, Salmonella may spread from the intestines to the blood stream and other organs, causing severe illness and possibly even death in vulnerable people. In severe cases patients may require treatment with antibiotics; however, some Salmonella bacteria have become resistant to many commonly used antibiotics.

Prevention

How can Salmonella infections be prevented?

Hand washing is one of the best ways to prevent the spread of foodborne illness.

It is also important to ensure you thoroughly cook foods to destroy bacteria. Contaminated foods may look and smell normal.

The following tips will help you reduce your risk of infection with Salmonella bacteria or other foodborne illnesses:

  • Bacteria can grow in the danger zone between 4 °C and 60 °C (40 °F to 140 °F). Keep cold foods cold at or below 4 °C (40 °F) and keep hot foods hot at or above 60 °C (140 °F).
  • Place raw meat, poultry and seafood in containers on the bottom shelf of the refrigerator. Use containers that are large enough to prevent raw juices from dripping onto other food or touching other food.
  • Keep raw food away from other food while shopping, storing, preparing and serving foods.
  • Wash fresh fruits and vegetables before eating them, clean counters and cutting boards and wash your hands regularly.
  • Read labels and follow cooking and storage instructions for all foods. Make sure to check the “best before” date, and if you find something on the shelf that has expired, let the store know.
  • Use warm soapy water to clean knives, cutting boards, utensils, your hands and any surfaces that have come in contact with food, especially meat and fish.
  • Refrigerate or freeze perishable food within two hours of cooking.
  • Freeze or consume leftovers within four days of cooking. Always reheat leftovers until steaming hot before eating.
  • Keep refrigerators clean and at a temperature below 4 C, or 40 F. Install a thermometer in your fridge to be sure.

If you think you are infected with salmonellosis or any other foodborne illness, do not prepare food for other people unless you wear disposable gloves and follow safe food handling procedures.

Surveillance

Does the Public Health Agency of Canada keep track of cases of salmonellosis across the country?

Yes, the Public Health Agency of Canada works with the provinces and territories to track the number of cases of salmonellosis across the country.

When people get sick and go to the doctor, those doctors in many cases take samples from the patients and send them to a provincial, territorial or federal lab for testing.

Those labs test the samples to identify the genetic fingerprint of the bacteria, virus or parasite responsible for the illness.

The lab then posts the results for bacterial illnesses on PulseNet Canada, a national network that allows microbiologists to track and share genetic fingerprints for comparison across the country.

All labs then compare their results with those posted on PulseNet to find matches and identify outbreaks.

PulseNet Canada is coordinated by the Public Health Agency of Canada’s National Microbiology Laboratory in Winnipeg.

Are salmonellosis outbreaks common in Canada?

Foodborne illnesses are relatively common in Canada. The Public Health Agency of Canada estimates that about 4 million Canadians suffer from a food-related illness each year.

Salmonellosis is the second most frequently reported food-related illness in Canada. Many of these illnesses are sporadic cases, but some are part of outbreaks.

A case refers to illness in one person whereas an outbreak refers to two or more people linked by a common exposure within a specific time frame.

A national outbreak occurs when illness is linked in two or more provinces or territories.

Protect yourself against food-borne illness by following safe food handling practices. For even more information about food safety, go to www.foodsafety.gc.caExternal Link.