Overview
Food poisoning results from eating food contaminated with bacteria, viruses, or their toxins. It typically causes nausea, vomiting, diarrhoea, and abdominal cramps, usually beginning within hours to days of eating contaminated food. Most cases are mild and resolve without treatment.
How common is it?
About 2.4 million cases of food-borne illness occur each year in the UK. Most are not reported to health services.
Causes and risk factors
Bacteria, viruses, or toxins from improperly handled, stored, or cooked food are the main causes. Common culprits include Salmonella (poultry, eggs), Campylobacter (chicken), norovirus (any food), and E. coli (undercooked beef).
Common risk factors
- Undercooked poultry, meat, or seafood
- Contaminated raw produce including salads
- Unpasteurised dairy products or juices
- Cross-contamination of raw and cooked foods
- Poor hand hygiene during food preparation
- Inadequate refrigeration or hot holding
- Eating at buffets where food sits at unsafe temperatures
Symptoms
- Nausea and vomiting
- Diarrhoea (sometimes bloody in bacterial infections)
- Abdominal cramps and pain
- Fever
- Headache
- Muscle aches
- Symptoms usually begin within 1 to 48 hours of eating contaminated food
When to see a doctor
Seek medical attention for bloody diarrhoea, fever over 38.5°C, diarrhoea lasting more than 3 days, signs of dehydration, or if elderly, pregnant, or immunocompromised. Some food-borne bacteria can cause serious illness requiring treatment.
Diagnosis
Stool culture identifies causative bacteria. Blood tests assess severity in hospitalised patients. Report suspected food poisoning to your local environmental health department to prevent wider outbreaks.
Treatments
Oral rehydration
Replace fluid and electrolytes with oral rehydration salts or drinks. Sip small amounts frequently. Water alone is insufficient as sodium and glucose are also lost.
Rest and bland diet
Rest the gut with clear fluids initially, then introduce bland foods as symptoms improve. BRAT diet (banana, rice, apple sauce, toast) is well tolerated.
Antibiotics for specific infections
Campylobacter, severe Salmonella, and some E. coli infections may require antibiotic treatment especially in high-risk groups. Not routinely used for mild food poisoning.
Self-care and lifestyle
- Cook chicken and minced beef until juices run clear (internal temperature 75°C)
- Refrigerate leftovers within 2 hours of cooking
- Keep raw meat separate from ready-to-eat foods in the fridge and on worktops
- Wash hands thoroughly before cooking and after handling raw meat
Prevention
Safe food handling practices, adequate cooking temperatures, proper refrigeration, and good personal hygiene during food preparation prevent most food poisoning. Avoid high-risk foods when pregnant or immunosuppressed.