Campylobacter is the most common identified cause of food poisoning.
Source
Raw poultry and meat, unpasteurised milk, and untreated water. Pasteurised milk can be contaminated by birds pecking bottle tops on the doorstep. Pets with diarrhoea can also be a source of infection.
Symptoms
The illness may be caused by only a small number of bacteria. Symptoms include fever, headache and a feeling of being unwell, followed by severe abdominal pain and diarrhoea which may be bloody. Symptoms normally take 2-5 days to appear but it can be as long as 10 days and return over a number of weeks.