Family Health Magazine
PREVENTION
Foodborne Illness
Was it something I ate?
Foodborne illness, often called food poisoning, strikes about two million Canadians and costs society over $1 billion each year. Since only about one in 25 cases is reported, it is hard to know the total effect.
Many people pass symptoms off as ‘stomach flu.’ At one time or another, all of us have probably had a foodborne illness. Symptoms may be mild and disappear in a few hours or days. In severe cases, a stay in hospital may be needed. It can even be fatal, especially in the very young and the elderly.
What causes foodborne illness?
If a food containing enough disease-causing bacteria, virus or toxins from bacteria is eaten, it causes foodborne illness. (Common bacteria and viruses causing foodborne illness are listed in Table 1.)
Table 1. Common bacteria and viruses that cause foodborne illness |
| NAME OF ORGANISM |
FOODS OFTEN INVOLVED |
INCUBATION PERIOD |
MAIN SYMPTOMS |
| Salmonella |
Undercooked chicken, turkey, eggs, meat; contaminated fruits and vegetables |
6 hours to
7 days |
Diarrhea, abdominal cramps, fever |
| E. coli O157:H7 |
Undercooked ground beef |
2 to 10 days |
Bloody diarrhea, abdominal cramps, fever |
| Campylobacter |
Undercooked chicken, hamburger; unpasteurized milk |
1 to 10 days |
Diarrhea, abdominal cramps, fever |
| Clostridium perfringens |
Stews, meat gravies held at improper temperatures after cooking |
6 to 24 hours |
Diarrhea, abdominal cramps, nausea |
| Staphylococcus aureus |
Deli-style foods (such as potato salad, sliced meats) kept at improper
temperatures |
1 to 6 hours |
Nausea, vomiting, abdominal cramps |
| Norovirus (formerly called ‘Norwalk virus’) |
Food handled by someone ill with norovirus infection |
10 to 50 hours |
Nausea, vomiting, abdominal cramps, diarrhea, headache, fever |
If you eat a food containing disease-causing bacteria, virus or toxin, symptoms will not appear right away. If toxins cause the foodborne illness, the incubation period (time between eating the food and getting sick) is a few hours.
If the foodborne illness is caused by an infection with bacteria or viruses, it usually takes 12 to 72 hours for symptoms to develop. In many cases, it takes more than three days. This means several meals may be eaten after the meal that caused the illness. We tend to blame foodborne illness on the last meal eaten, but it may have been caused by a meal eaten days before!
Why does foodborne illness occur?
Foodborne illness usually occurs when food is handled in a way that causes it to become contaminated or allows germs to grow or survive in it.
- Foods can become contaminated by germs from unwashed hands, or from unclean equipment and work surfaces contaminated by raw foods.
- Germs can grow in food kept at temperatures favourable for growth: 4 C (40 F) to 60 C (140 F). This is known as the danger zone. If food is kept colder or hotter, germs cannot grow in it.
- Bacteria can survive in food that is inadequately cooked or processed.
How does foodborne illness occur in the real world?
Since foodborne illness is so serious, public health officials track how it develops. These cases describe actual outbreaks and what went wrong with the food handling and preparation.
- A restaurant employee came to work while ill with diarrhea. She did not wash her hands properly after going to the toilet. Salmonella bacteria on her hands likely contaminated the foods she handled. Thirty-five people who ate at the restaurant became ill with Salmonella infection. Nine were so sick that they were admitted to hospital.
- The caterer for a 200-person wedding banquet prepared mushroom gravy on the stove on the day of the banquet. After heating the gravy, the stove burner was turned off. The gravy was left unheated for six hours. It was warmed only slightly before being served to the wedding guests. Within 12 hours of the banquet, more than 100 guests became ill with diarrhea. The mushroom gravy was found to contain high numbers of Clostridium perfringens bacteria. These bacteria survive cooking, and likely grew in the gravy when it was held at room temperature.
- In 1993, 583 people in the U.S. became ill with E. coli O157:H7 infection after eating at the same restaurant. Four people died because of their illness. Undercooked hamburger patties probably caused the outbreak.
Can foodborne illness be prevented?
Environmental health officers and other food inspectors work hard to make sure your groceries and restaurant meals are safe and wholesome. At home, however, you must assume the role of inspector. Follow the rules for safe food handling to keep foodborne illness from becoming the uninvited guest at your dinner table.
Prevent bacteria from growing in food
- Keep hot foods hot (above 60 C/140 F) and cold foods cold (below 4 C/40 F).
- Keep your refrigerator colder than 4C. (You might want to place a thermometer in the fridge, just to be sure.)
- Place leftovers in the fridge or freezer immediately after the meal. Store leftovers in small amounts so they will cool faster.
- Throw away perishable foods left at room temperature for more than two hours.
Prevent contamination of foods
- Wash your hands often – before handling food, after handling raw meats or poultry, after using the toilet, after changing a diaper, and whenever else necessary.
- Avoid preparing food for others if you are vomiting or have diarrhea.
- Wash fruits and vegetables before eating them.
- Clean food equipment well with hot soapy water after the equipment has been in contact with raw meat or poultry. This includes cutting boards, knives, containers and work surfaces. For added safety, wipe equipment with a bleach solution (1 tablespoon/15 mL bleach per 1 gallon/4 L of water) after cleaning.
- Use only a freshly laundered dishcloth for kitchen cleanup (not one that may have been contaminated during food preparation).
Keep bacteria from surviving in foods
- Thoroughly cook all meat and poultry to temperatures above 74 C/165 F before serving. Use a meat thermometer to check that this temperature has been reached.
- Reheat leftovers thoroughly (to above 74 C/165 F) before serving.
How do I know a restaurant is safe?
Although environmental health officers work with restaurants to maintain food safety, they cannot be everywhere at once. When eating out, check to see if staff follow proper food handling procedures. Watch for:
- unclean conditions (dirty floors or walls) in the dining room
- food that is not properly cooked, such as underdone hamburger or poultry
- perishable food stored at room temperature
- poor hygienic practices by staff serving or preparing food
- evidence of insects, rodents or other pests
- dirty cutlery or dishes.
If you notice any of these things, consider calling your local health department. An environmental health officer will investigate to ensure food safety issues are corrected.
What should I do if it happens to me?
If you think that you or someone in your household has a foodborne illness, do the following.
- Visit your doctor, especially if symptoms are severe. A stool specimen can help determine if the symptoms are the result of a foodborne illness.
- Contact your local health department. Reporting the illness can help identify outbreaks. You will likely be asked what you ate in the days prior to the illness. The more details you can provide, the more likely the health department will be to pinpoint the food causing your illness
While effort is made to reflect accepted medical knowledge and practice, articles in Family Health Online should not be relied upon for the treatment or management of any specified medical problem or concern and Family Health accepts no liability for reliance on the articles. For proper diagnosis and care, you should always consult your family physician promptly. © Copyright 2012, Family Health Magazine, a special publication of the Edmonton Journal, a division of Postmedia Network Inc., 10006 - 101 Street, Edmonton, AB T5J 2S6 [PR_FHb08]
