There are many causes of foodborne illness, such as:
- Improperly cooked food
- Improperly stored food
- Contamination of food by ill food preparer
- Contamination of food by other contaminated food
- Contamination of food from environmental sources (dirt, animal feces)
Some foods commonly have bacteria on them when purchased. This is why raw or undercooked chicken can be dangerous.
The risk of exposure to food borne bacteria and viruses can occur in the home, in restaurants and at community meals like a church supper.