Salmonella is a bacteria that causes food poisoning.
Where does it come from?
Found in intestines of many animals, so may be in animal faeces.
How is it spread?
- By eating or drinking food contaminated with faeces that has the bacterium in it.
- Unvaccinated chickens may have it in their eggs.
- Eating raw food that contains the bacteria.
Large numbers of the bacteria are needed to cause disease, so it is normally caught if food has been left to stand around in warm, damp conditions.
How does it cause food poisoning?
- The bacteria invades the lining of the small intestine,
- They rapidly divide here,
- When they die, they release an endotoxin when they burst open,
The endotoxin causes the symptoms of food poisoning:
- vomiting
- diarrhoea
- abdominal pain
- fever
- dehydration
What is the treatment?
They are often left to run their course. Drink lots of water and rest.
In the young or elderly, oral rehydration therapy is given. This is a drink containing sugar and salts, which replaces mineral ions lost in the body.
Antibiotics are only given in severe cases.
How can we prevent food poisoning?
- If food is frozen, allow it to completely thaw and then cook all the way through – this will kill any bacteria. If it’s cooked before defrosting completely, some parts of the chicken might not heat up enough to kill the bacteria,
- Wash your hands before handling food,
- Dispose of bleach old dish clothes regularly,
- Don’t mix raw meat with anything else.
Year 12 Human Biology 