Food Poisoning


This fact sheet provides basic general information only and is to be used as a quick guide, not as a complete resource on the subject. If you have any further questions, ask your own physician, local health unit or health care worker.

Beware What You Eat!!

It's barbecue season! And we'll be eating more undercooked meat, salads made from fresh vegetables that may not be washed properly, and foods left out in the heat. Altogether this is a recipe for food poisoning !

An estimated 2.2 million Canadians become ill each year from contaminated food (ref. Health Canada). In Ontario, approximately 70 outbreaks per year are associated with food poisoning (ref. MOH Ontario). Most cases are caused by mishandling food, and are preventable.

What is Food Poisoning?

Food poisoning is a generic term which refers to enteric illnesses caused by eating food contaminated by bacteria or parasites. Many bacteria can cause food poisoning, such as Salmonella, E. coli, Campylobacter and Staphylococcus. Parasites implicated in food poisoning include Giardia and Cyclospora.

Symptoms of food poisoning occur from a few hours to a few weeks after consumption of contaminated food, and may include cramping, diarrhea and nausea/vomiting. Serious cases may progress to include fever and dehydration.

What Foods Are At Risk?

Foodborne illness is usually associated with meats, poultry, seafood and dairy products, but recently more attention has been focussed on fruits and vegetables. The major culprits are listed below:


Poultry and eggs are the major sources of Salmonella bacteria, and to a smaller extent Campylobacter bacteria. Salmonella infections usually occur within 12 to 36 hours after eating poorly cooked poultry or foods containing raw or undercooked eggs or egg products (eg. eggnog).

Poultry should always be cooked thoroughly to an internal temperature of 74 degrees Celcius (140 degrees Fahrenheit). Slow cooking at low temperatures of large turkeys should be avoided. If poultry is cooked properly the meat should be white and the juices should run clear. Poultry should always be stuffed just before cooking, since it contains raw eggs. Extra stuffing may be cooked on the stovetop and then be refrigerated until ready to serve.

Avoid the use of raw eggs and never use dirty or cracked eggs.


Hamburger meat is the major source of the bacteria E.coli (type 0157:H7), which can cause haemorrhagic colitis and haemolytic uremic syndrome; and Yersinia which can cause acute diarrhea and colitis with a fever. Both infections can occur from 3 to 8 days after eating contaminated meat.

Care should be taken with raw hamburger to avoid contaminating other foods. After preparing meatballs or patties with the hands, wash well with soap and hot water before touching salad vegetables or other food that will not be cooked. Never use the same utensils or dishes for other foods after using them to prepare raw meat until they have been thoroughly cleaned and dried. Always use a clean platter for cooked meat.

Hamburger should never be eaten raw. Always be sure the inside of the meat has lost all trace of pink colour. Never leave raw hamburger out of the fridge long enough to get warm. Bacteria multiply by the millions as the temperature reaches that of room air!

Salad Vegetables and Fruit

Food poisoning is usually associated with meat, but 5% of outbreaks are attributed to fruits and vegetables (ref. U.S. Centres for Disease Control). The main source of contamination is from fertilizer derived from animal faeces (eg. manure). Since many vegetables and fruits are eaten raw, the bacteria in the soil clinging to the food do not get killed.

To safeguard against infection, be sure to refrigerate raw fruits, vegetables and salads, to keep bacteria from multiplying. Wash and peel fruit and mushrooms before eating. Wash raw vegetables well before use, preferably using a vegetable brush. Peel vegetables whenever possible.

Never prepare raw vegetables on a cutting board that has been used for raw meat. It is best to have two cutting boards - one for meat and one for vegetables. And be sure to wash your hands well after cleaning fruit and vegetables.

Dairy Products

Unpasteurized milk and cheese products are associated with several bacterial agents, such as Campylobacter, Yersinia and Listeria. Campylobacter infection may be mild to severe, and is one of the bacteria responsible for "traveller's diarrhea". Infections occur from 3 to 5 days after ingestion of contaminated food.

Listeria infection can occur from 3 days to 2 months following exposure to contaminated food. The most susceptible individuals are adults over age 40 and newborn infants. Symptoms are often flu-like, with fever, malaise and nausea/vomiting.

Raw milk should never be consumed without heat-treating beforehand. Unpasteurized cheese should be eaten only if cooked.

Other Things to Beware!

The list goes on! Botulism is an illness resulting from ingesting toxin produced by Clostridium bacteria. These bacteria grow in the absence of air, and are introduced into foods that are canned or preserved. The bacteria multiply in the airless environment, and produce a toxin that affects the nervous system, causing paralysis. Symptoms appear 12 to 36 hours after ingestion of contaminated food. Be sure all preserved foods are cleaned and cooked well, and never eat canned or preserved foods that appear to be discoloured, foul-smelling or that have gas bubbles in them.

Staphylococcal food poisoning is one of the most common types of foodborne illness, particularly in the summer months when temperatures are warm and foods are left out in the heat for longer periods of time. Staphylococcus is carried on the hands and skin, and is introduced into food when the hands are not washed prior to preparing foods. Symptoms occur rapidly, from 2 to 4 hours after eating contaminated food, and may include nausea, cramps, vomiting and diarrhea. The most susceptible foods are sauces, custards, salad dressings, meat products and sliced or chopped foods. Keep foods refrigerated or cool until just before eating, and dispose of leftover foods. Be sure to wash hands thoroughly before preparing foods and use only clean utensils. Persons with skin or eye infections should not prepare food.

General Rules to Prevent Food Poisoning

Follow these tips to help reduce the risk of food poisoning in your kitchen:

1. Always wash your hands before and after touching food, especially raw meat, fish and poultry.

2. Never prepare raw meat and uncooked vegetables at the same time without washing your hands in between.

3. To prevent cross-contamination, use a polyethylene cutting board for raw meat, fish and poultry, and a separate board for fruits and vegetables.

4. To kill the bacteria that collect on cutting boards, give them a scrub weekly with 1:4 mixture of bleach and water, then rinse with cold water.

5. Always use a clean platter for cooked meat, not the same platter that was used for raw meat.

6. Do not allow raw or cooked foods to sit for long periods at room temperature.

7. Keep hot food at 60 degrees Celcius (140 degrees F) or hotter.

8. Keep cold food at 40 degrees Celsius (4 degrees F) or colder.

9. Never serve undercooked poultry or hamburg.

10. Plan your cooking so there are few or no leftovers. When you have large amounts of leftovers, pack them into small packages and chill them quickly.

11. Avoid raw eggs and dairy products.

12. Stuff poultry just before roasting.

Bon Appetit!!