What causes foodborne and waterborne illness?
Foodborne and waterborne illness result from the failure to control an identified (or unidentified) hazard. What is a hazard? There are many ways to describe a hazard. In its simplest form, a hazard is something that has the potential to cause harm. In food and water, it is an unacceptable contamination that causes the food or water to be unfit for human consumption.
A hazard falls into 3 categories: physical, chemical and biological. Foodborne disease has the potential to be caused by all three of these categories of hazards.
1. Biological foodborne illness is by far the most common occurrence of foodborne illness and is caused by a large number of pathogenic (disease-causing) microorganisms (germs), including viruses, bacteria, protozoa, parasites and fungi. A very common virus that causes foodborne illness is norovirus (people often call illness caused by this virus "stomach flu", although it is not really a true "flu", which is a respiratory illness). Salmonella bacteria also commonly cause foodborne illness.
2. Chemical illness arises from substances that do not belong in food, but can contaminate it through carelessness or malicious intent or simply by contact with the food. Pesticides and cleaners are some of the chemicals that can cause harm through food. For example, bleach can cause poisoning and should only be kept in a clearly marked container to avoid contaminating food. Paralytic shellfish poisoning (PSP) toxin in mussels, clams and oysters is an example of a chemical hazard that can cause illness.
3. Physical foodborne illness (injury, in this case) results from foreign objects in food like wood splinters, glass and metal fragments, pebbles or bone fragments.
Waterborne disease falls into 2 of these categories: chemical and biological. Many of the pathogens that cause foodborne illness also cause waterborne disease. Because water systems often serve large numbers of people, outbreaks of disease can also be very large.
What are the symptoms of food and waterborne disease?
The symptoms of physical and chemical causes of illness and injury will vary considerably:
- Foreign objects in food can cause broken teeth or internal bleeding
- Chemicals in food or water can cause burns to the stomach and intestines, neurological (nerve) effects such as tingling, numbness and many other symptoms, or chronic (long term) problems such as cancer
- Biological causes will affect primarily the stomach and/or intestines, since food and water are taken internally, and can include:
In certain types of foodborne illness, more severe life-threatening symptoms or long term symptoms may show up. A long term symptom resulting from some E. coli O157:H7 infections is kidney damage, called hemolytic-uremic syndrome (HUS).
How can you prevent food and waterborne disease?
- Food: eat only food that is from approved sources. Follow the 4 basic rules of
- Separate (don't cross-contaminate)
found at www.canfightbac.org.
- If you draw water from a community water system, find out who operates it and pay attention to any advisories they provide.
- If you draw water from a private well, you may consider having it tested. Get rid of any sources of chemical or biological contamination and consider treating the water.
- If you draw water from a surface supply like a lake, stream or dugout, or if you have a shallow well (which will most likely be influenced by surface water), you should treat it to get rid of any pathogens.
For more information, visit Food and Your Health http://www.bccdc.ca/foodhealth/default.htm and the HealthLink BC website at http://www.healthlinkbc.ca/healthfiles/httoc.stm or contact your local health authority.