Foodborne illness (also known as foodborne disease and food poisoning) is any illness resulting from the contamination of food by pathogenic bacteria, viruses, or parasites, as well as prions (the agents of mad cow disease), and toxins such as aflatoxins in peanuts, poisonous mushrooms, and various species of beans that have not been boiled for at least 10 minutes. While contaminants directly cause some symptoms, many effects of foodborne illness result from the body's immune response to these agents, which can vary significantly between individuals and populations based on prior exposure.
Symptoms vary depending on the cause. They often include vomiting, fever, aches, and diarrhea. Bouts of vomiting can be repeated with an extended delay in between. This is because even if infected food was eliminated from the stomach in the first bout, microbes, like bacteria (if applicable), can pass through the stomach into the intestine and begin to multiply. Some types of microbes stay in the intestine.
