Food poisoning

Causes and symptoms

Eating habits are changing. More food is now eaten some time after its original preparation. This means that safe food handling to prevent food poisoning is becoming more important.

Eating food contaminated with harmful amounts of bacteria, viruses and, less commonly, parasites that our bodies do not tolerate causes food poisoning.

Common symptoms include:

  • nausea;
  • stomach pains;
  • vomiting;
  • diarrhoea; and
  • headache.

How does food become contaminated?

Bacteria are everywhere — in the air, soil and water. Insects and animals (including humans) carry bacteria and will contaminate any surface they touch.

In the right conditions (moisture and warmth), bacteria multiply, producing large colonies in food within several hours. Food affected in this way may still appear wholesome and normal, unlike obviously ‘off’ food that tastes and smells unpleasant. Meat, poultry, seafood, eggs, dairy products, prepared salads (including fruit salads) and cooked rice are especially vulnerable.

Viral food contamination can occur when people who are handling foods are infected with certain viruses, or when food is washed or grown in contaminated water.

Preventing food poisoning

You can protect your family from food poisoning by following these rules.

  • Store cold and frozen food in the refrigerator or freezer as soon as possible after purchasing.
  • Wash hands with soap and warm water before handling food and between handling raw and cooked foods.
  • Check the refrigerator temperature is between 0° and 4°C and the freezer is below -15°C.
  • Thaw frozen food in the refrigerator or microwave to prevent bacteria growing on the outside while the inside remains frozen.
  • Keep raw and cooked foods well separated in the refrigerator.
  • Don't allow raw food to re-contaminate cooked food by using the same knife or chopping board.
  • Serve cold food straight from the refrigerator.
  • Hot foods should be kept at simmering point.
  • Cooked foods that will not be eaten immediately should be cooled quickly and refrigerated.
  • Leftovers should be reheated to steaming hot (at least 75°C in the centre of the food) where possible.
  • Rinse dishcloths with hot water and allow them to dry between uses.
  • Avoid preparing food for others when you are sick, especially during or immediately after an episode of gastroenteritis.
Last Reviewed: 28 February 2013
Your Doctor. Dr Michael Jones, Medical Editor.

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References

1. Food Standards Australia New Zealand. Food poisoning (updated Sep 2012). http://www.foodstandards.gov.au/scienceandeducation/factsheets/factsheets/foodpoisoning.cfm (accessed Mar 2013).
2. Centers for Disease Control and Prevention (CDC). Food safety (updated 28 Jun 2011). http://www.cdc.gov/foodsafety/facts.html (accessed Mar 2013).
3. MayoClinic.com. Food poisoning (updated 16 Jun 2011). http://www.mayoclinic.com/health/food-poisoning/DS00981 (accessed Mar 2013).
Dr Michael Jones

Dr Michael Jones

Medical Editor, Your Doctor.