Food Matters

Foodborne Illness

Foodborne illness may be either infectious or toxic in nature and is caused by the consumption of contaminated food or drink.

Those illnesses of an infectious nature ('foodborne diseases') comprise:

• Food Poisoning
  In which, with just a few exceptions (e.g. Clostridium botulinum), food poisoning occurs only after a very large number of bacteria (10⁵ - 10⁶ per gram of food) or a large quantity of bacterial toxin has been ingested. Most food poisoning symptoms affect the gastrointestinal tract and typically include abdominal pain, diarrhoea and vomiting, although fever, malaise and general weakness may also be experienced. The incubation period is comparatively short (from a few hours to a few days) and is influenced by the number of bacteria that have multiplied in the food and the particular individual's response. Illness may last from several hours up to about a week. Examples of pathogens in this category include Salmonella species, Staphylococcus aureus and Clostridium perfringens.



• Foodborne Infection
  In which infection is caused by relatively few microorganisms which develop in the body of the victim, generally over a longer period than occurs with food poisoning. As the infective dose is usually small, bacteria need not necessarily multiply to large numbers in food before consumption in order to cause illness. Symptoms can be severe, and include kidney disease, septicaemia, meningitis and abortion/still-birth. Examples of pathogens in this category include Campylobacter jejuni, Escherichia coli O157:H7 and Listeria monocytogenes.



• Foodborne Parasite Infection
  In which infection is caused by one of a number of foodborne parasites. Infection can arise from the (accidental) consumption of small numbers of parasites in contaminated food and give rise to symptoms that can range from nausea, diarrhoea and vomiting to inflammation, abscesses, brain seizures and blindness. Examples include Cryptosporidium parvum, Giardia lamblia and Taenia solium.

The remaining category of foodborne illness is that arising from the consumption of chemical toxins.

Chemical Food Poisoning
The term given to foodborne illnesses that arise from the consumption of chemical toxins. This may produce acute or chronic illness due to the consumption of harmful chemicals present in food. Chemical food poisoning may result in a wide range of symptoms or conditions, ranging from those affecting the gastrointestinal tract (diarrhoea and/or vomiting) to ones that affect the nervous system, and others that lead to cancer. Examples of chemical food poisoning include shellfish contaminated with toxins, poisonous plants and fungi, poisonous fish and shellfish, mycotoxins (produced by moulds) and a variety of chemical contaminants.