Bags of tomatoes are tested for salmonella bacteria at a U.S. government lab in California, during a salmonella outbreak in 2008. (Kevork Djansezian/Associated Press)As many as 13 million Canadians will experience the discomfort of food-borne illness every year. For most, it'll mean a few days of nausea, vomiting or diarrhea. But it can also be deadly, especially if you're in a high-risk group.

Listeria is more likely to kill than any other bacteria that cause food poisoning. For high-risk groups — pregnant women and their unborn or newborn children, the elderly, and people with weakened immune systems — listeria can be fatal in 20-30 per cent of cases.

In most cases of food poisoning, the problem can be traced back to the kitchen and consumers can take some simple steps to avoid getting sick. Hand washing, refrigeration, proper cooking and disposal of expired or questionable foods can go a long way to preventing food-related illness.

Common types of food poisoning

Listeria

Michael McCain, president of Maple Leaf Foods, holds media briefing on new food safety protocols at its new meat packaging plant in Laval, Que., Dec. 12, 2008. A listeriosis outbreak linked to 20 deaths was traced back to tainted meat at a Maple Leaf Foods plant in Toronto earlier that year. (Ryan Remiorz/Canadian Press)Source: The bacterium Listeria monocytogenes, commonly referred to as listeria, is found in soil, vegetation, sewage, water and the feces of animals and humans. Listeria bacteria can also be found in unpasteurized dairy products, raw vegetables and meats and processed foods including deli meats and hot dogs.

Eating foods spoiled with Listeria monocytogenes can result in serious illness, including brain and blood infections and in extreme cases death.

Symptoms: Nausea, vomiting, stomach cramps, diarrhea, constipation, severe headache, persistent fever and stiff neck, among others.

Symptoms can appear up to 70 days after exposure to the bacteria. Listeria is killed during the cooking process, so it is crucial to properly cook your food.

Campylobacteriosis

Source: Bacteria is transmitted through untreated surface water, poultry, beef, swine, rodents, wild birds and household pets.

Symptoms (may include): Fever, headache and muscle pain, followed by diarrhea, stomach pain, cramps, nausea and vomiting. Symptoms appear within 2 to 5 days after exposure.

Botulism

Source: The bacteria that cause botulism grow from home-canned, low-acid foods such as corn, green beans and mushrooms. Botulism is also linked to raw or parboiled meats from marine mammals.

Symptoms (may include): Nausea, vomiting, fatigue, dizziness, headache, double vision, dryness in the throat and nose, paralysis.Symptoms occur from 12-36 hours after infection. With treatment the fatality rate in Canada is about 10 per cent.

Cyclosporiasis

Source: Cyclospora is a parasite that is transmitted through food or water which is contaminated by human feces.

Symptoms (may include): Diarrhea, loss of appetite, weight loss, nausea, gas, stomach cramps, muscle aches, vomiting, fever, bloating and fatigue Onset of symptoms happens approximately one week after infection.

Salmonellosis

Source: Salmonella bacteria develop from raw or undercooked meat (especially poultry), unpasteurized milk and milk products, eggs, sprouts, raw fruit and vegetables (if they have been contaminated by an infected surface or dirty hands).

Symptoms (may include): Diarrhea, abdominal cramps, vomiting, fever. Symptoms appear six to 72 hours after exposure.

Toxoplasmosis

Source: Cross-contaminated or undercooked meat. Contamination is also possible through gardening or changing cat litter (cat feces are a common source of Toxoplasma gondii, the bacteria that causes toxoplasmosis.)

Symptoms (may include): Fever, enlarged lymph nodes, and other flu-like symptoms. Symptoms may not appear for 5-18 days after exposure.

Escherichia coli

Source: Cross-contamination occurs from food to food, person to person, or person to food. E. coli bacteria often originate in the intestines of cattle, poultry and other animals.

Symptoms (may include): Some people don't get sick at all. Others have flu-like symptoms that can include stomach cramps, vomiting and a mild fever and diarrhea. Onset of symptoms can occur within 2 to 10 days of eating contaminated food. About 10% of people infected with E. coli develop Hemolytic Uremic Syndrome, which is a blood disorder marked by kidney failure.

Bacillus cereus

Source: This bacterium normally infects people through improperly cooked food. It is responsible for two to five per cent of food-borne illnesses. Some strains of B. cereus are beneficial to animals like chickens, rabbits and pigs, as they compete with Salmonella and CampylobacterI in the gut, reducing the number of those harmful bacteria — and making them safer for people to eat.

Symptoms (may include): Nausea, vomiting and diarrhea. The strain that leads to diarrhea is caused by eating improperly cooked meant. It usually hits eight to 16 hours after consumption of contaminated food. The strain that leads to vomiting is usually caused by eating rice that has not been cooked long enough or at a temperature high enough to kill spores. You usually feel sick between one and five hours after eating contaminated rice.

Prevention

The most effective way to prevent food poisoning is to ensure food quality and prevent cross-contamination.

• Purchase only undamaged packaged products and pay attention to expiry dates.
• Only buy meat and fish products from reputable retail outlets.
• Drink only pasteurized milk, juice and cider.

Follow the basic food safety steps:

Clean: Always wash hands with soap and hot water for 20 seconds before and after handling food. Also be sure to sanitize cooking equipment, utensils and surfaces before and after use. Only use clean water in gardens and to wash and prepare food. And only harvest and eat food from water that is clean.

Separate: Keep raw items such as beef or vegetables away from others while shopping, storing, and preparing food.

Chill: Refrigerate below 4 C (40 F) and freeze below -18 C (0 F).

Cook: Food must be cooked to the proper temperature and kept warm at temperatures above 60 C (140 F).

Chicken should be cooked to 82-85 C (180-185 F) and turkey to 77 C (170 F)

Beef steaks and roasts should be cooked as follows:

• Medium rare 63 C (145 F).
• Medium 71 C (160 F).
• Well 75 C (170 F).

Pork should be cooked to 71 C (160 F)