Describe one Food Borne Disease

On Saturday, August 23rd., 2008, the Public Health Agency of Canada announced that 21 cases of a deadly listeriosis outbreak have been confirmed and another 30 are under investigation. Of the confirmed cases, sixteen have occurred in Ontario, three in British Columbia, one in Saskatchewan and one in Quebec.

Four deaths in Ontario have resulted from the disease so far.

Until recently, this disease has been unknown to most Canadians. Here are some pertinent facts of which we should be aware, in light of the growing outbreak.


Listeria monocytogenes (commonly called listeria) is a type of bacteria which is common in the environment. Animals and humans can carry the bacterium without even knowing it. Farm animals may appear healthy and still be carriers. They may contaminate foods such as meats and dairy products. Listeriosis is a food borne illness.

Foods contaminated with listeria look, smell and taste normal. The bacteria can live and even multiply on food stored in the refrigerator. It can be killed by proper cooking procedures.


Symptoms start suddenly and include persistent fever, chills, muscle and joint pain, fatigue, nausea, vomiting, cramps, diarrhoea, headache, or constipation. At this stage the illness may be mistaken for food poisoning.

If the disease spreads to the nervous system, these further symptoms may be noted: severe headache, stiff neck, confusion, loss of balance and convulsions. Meningitis encephalitis (an infection of the brain or its surrounding tissues) and /or septicemia (blood poisoning) may develop. Either of these conditions can result in death.


Symptoms can appear from 2 to 90 days after consuming contaminated food. Average incubation period is three weeks.

Most at risk

Most at risk are pregnant women and their unborn children, those with weakened immune systems and the elderly.


There is no vaccine for listeria. The disease is treated by antibiotics. Early diagnosis is critical, especially for those at high risk.


Diagnosis is done through a blood test. Sometimes spinal fluid, urine, stool samples or amniotic fluid may also be tested.


* Refrigerate food at 4 degrees C or colder.

* Thoroughly cook foods such as hot dogs and poultry products.

* Avoid unpasteurized milk and dairy products.

* Wash all raw fruit and vegetables well before eating.

* Follow “use by” dates on packaged goods.

* Follow all package directions for food preparation and storage.

* After handling food in the kitchen, especially raw meat and fish, thoroughly clean and sanitize all surfaces with a solution of bleach and water ( 5 ml of bleach to 750 ml of water). Rinse.

Refrigerate or freeze leftovers within 2 hours.

* Frequently wash and disinfect the refrigerator.

* Defrost food in the refrigerator, in cold water, or in the microwave, but never at room temperature.

* Wash hands frequently, especially before and after handling food.

Foods to Avoid (especially by high-risk individuals)

It is wise to avoid:
– hot dogs
– non-dried deli-meats
– cheese made from unpasteurized milk
– refrigerated pate and meat spreads
– refrigerated smoked seafood and fish
– raw or undercooked meat, poultry and cook.

With attention and care, the people of Ontario and Canada can overcome this outbreak of listeria, learn from it, and take measures to ensure that it will not be repeated.