Introduction
Food poisoning is a widespread and potentially dangerous condition caused by various factors. It is most commonly caused due to infections with microbes. Additionally, harmful chemicals can also lead to food poisoning. These harmful agents can contaminate food at any stage, from the moment it is grown, harvested, or slaughtered to processing, storage, shipping, and preparation. This blog delves deeper into the primary causes of food poisoning, categorising them into bacteria, parasites, and viruses.
How is food poisoning caused?
A variety of factors can cause food poisoning. Here's a detailed breakdown of the causes of food poisoning:
1. Bacteria
Bacteria are the most common cause of food poisoning. Numerous bacteria, some of which are well-known and others less so, can lead to foodborne illnesses. The major bacterial causes of food poisoning include:
- coli (Escherichia coli): Some strains of E. coli, particularly Shiga toxin-producing E. coli (STEC), can cause severe food poisoning. Consumption of contaminated meat or other foods can lead to infections that result in symptoms like diarrhoea, abdominal pain, and, in severe cases, kidney damage.
- Listeria monocytogenes: Listeria is responsible for a severe foodborne illness called listeriosis. It can be found in contaminated deli meats, unpasteurized dairy products, and various ready-to-eat foods. Listeriosis can be particularly dangerous for pregnant women and individuals with weakened immune systems.
- Salmonella: Salmonella is a widespread bacterial cause of food poisoning. It can be present in various foods, including poultry, eggs, and dairy products. Symptoms of salmonellosis include diarrhoea, fever, and abdominal cramps.
- Campylobacter: Campylobacter is often associated with undercooked poultry. Infection can lead to symptoms like diarrhoea, nausea, and vomiting.
- Clostridium botulinum: This bacterium is responsible for botulism, a rare but severe food poisoning. It thrives in improperly canned or preserved foods. It produces a potent neurotoxin that can lead to paralysis and respiratory failure.
- Staphylococcus aureus: Staphylococcal food poisoning is caused by consuming foods contaminated with Staphylococcus aureus bacteria. Symptoms include nausea, vomiting, and abdominal cramps.
- Shigella: Ingesting food or water contaminated with Shigella bacteria can lead to shigellosis, a foodborne illness characterised by diarrhoea, fever, and abdominal pain.
- Vibrio vulnificus: This bacterium is commonly associated with raw or undercooked seafood, especially oysters. Infection can result in severe gastrointestinal symptoms.
2. Parasites
While food poisoning caused by parasites is less common than that caused by bacteria, it is still a serious concern. Parasites can live in the digestive tract and may go undetected for extended periods. Parasitic causes of food poisoning include:
- Toxoplasma gondii: Toxoplasmosis is a leading cause of death attributed to food poisoning in the United States. This parasite can be found in cat litter boxes and is associated with undercooked or contaminated meat.
- Giardia lamblia: Giardia is a parasite that can be present in contaminated water and food, leading to gastrointestinal symptoms.
- Various Tapeworms: Different types of tapeworms, such as Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), and Diphyllobothrium latum (fish tapeworm), can be transmitted through undercooked or raw meat or fish.
- Cryptosporidium: This parasite is a leading cause of waterborne diseases and can cause severe gastrointestinal symptoms.
3. Viruses
Viruses can also cause food poisoning, the Norwalk virus being the most common viral cause. Other viruses that bring on symptoms like vomiting and diarrhoea include rotavirus, astrovirus, sapovirus, and hepatitis A. Norovirus causes millions of gastroenteritis cases in the United States each year, with rare cases turning fatal.