Causes of Food Poisoning

Food poisoning is an illness caused by eating or drinking food or water that is contaminated with germs or their toxins. It is very common and usually short-lived.

Bacteria

• Salmonella, often from raw or undercooked eggs, poultry and meat
• E. coli, from undercooked meat, raw vegetables or contaminated water
• Campylobacter, mostly from undercooked chicken and unpasteurised milk
• Staphylococcus aureus, where food handlers' germs produce a toxin in food left out
• Bacillus cereus, often from rice or starchy food kept warm for hours
• Clostridium species, including botulism from improperly preserved food
• Vibrio cholerae and Shigella, from contaminated water or street food
• Listeria, from unpasteurised dairy and ready-to-eat foods, a particular risk in pregnancy

Viruses

• Norovirus, very contagious, spread by infected people and shellfish
• Rotavirus and hepatitis A, spread through water and food handled by infected people

Parasites and toxins

• Giardia and other parasites in contaminated water
• Natural toxins, such as in some mushrooms, certain fish and mould-contaminated grains

How food becomes unsafe

• Poor hand washing or unclean utensils
• Raw and cooked food stored together
• Food left at room temperature, especially in hot weather
• Undercooked meat, eggs or seafood
• Unsafe water, ice or unwashed vegetables

The Ayurvedic view

Ayurveda links this to indigestion with toxic residue (ama), and describes sudden vomiting and diarrhoea under visuchika and ajirna. This is an interpretive, traditional framework.

Why it matters

Knowing the source helps prevent repeat illness and spot outbreaks.