A tiny amount of contaminated food is enough to cause severe illnesses such as food poisoning, typhoid, cholera, hepatitis A and traveller's diarrhoea. Most cases of food poisoning are associated with improper cooking or storage of foods, and by poor hygiene (not washing hands before handling food). Food that has been left out for longer than two hours are also a source of poisoning. Some of the food may have residual chemicals that may cause poisoning if the food is not properly prepared. Meat can become contaminated during slaughter when animal stools is mixed with the beef. If you are unsure about the safety of the food, throw it away. Swimming in or drinking sewage-contaminated water is also a source of poisoning. About 20 organisms can cause food poisoning. This includes bacteria and viruses. Eating food contaminated with these organisms can lead to nausea, vomiting, abdominal cramps and diarrhoea. Vomiting and diarrhoea are the body's way of getting rid of the toxin. Symptoms of food poisoning may occur hours to several days after eating contaminated food. First Aid Most cases of food poisoning will settle within a few hours to days. Drink lots of fluid to prevent dehydration. Drink small sips of clear juice and soup. Do not induce vomiting. It may not remove all the bacteria that can cause illness. Do not self-treat with anti-diarrhoeals or antacids as they are usually ineffective.