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Food poisoning
14-minute read
Key facts
- Food poisoning is caused by bacteria, viruses or toxins in the food we eat.
- Symptoms of food poisoning range from mild to very severe.
- Most cases of food poisoning don’t need medical attention.
What is food poisoning?
Food poisoning is caused by bacteria and viruses getting into the food we eat. It can also be caused by toxins produced by bacteria such as Staphylococcus aureus.
Food poisoning is also called ‘foodborne illness’.
What are the symptoms of food poisoning?
Symptoms of food poisoning can range from mild to very severe. You may be sick with food poisoning but not know what food caused it. Different bacteria and viruses cause different symptoms.
If you have food poisoning, you’ll probably have gastroenteritis symptoms such as:
Symptoms can take between a few hours to a few days to start, depending on the cause of your food poisoning.
Salmonella |
|
|---|---|
| Symptoms | Headache, fever, abdominal cramps, diarrhoea, vomiting and nausea |
| How long it takes for symptoms to appear | Between 6 and 72 hours |
| How long symptoms last for | 2 to 5 days |
| Foods the infection is typically found in | Undercooked poultry, raw egg desserts, mayonnaise, sprouts, tahini |
Campylobacter |
|
|---|---|
| Symptoms | Fever, nausea, abdominal cramps and diarrhoea (sometimes bloody) |
| How long it takes for symptoms to appear | Between 2 to 5 days |
| How long symptoms last for | About 5 days |
| Foods the infection is typically found in | Raw and undercooked poultry, unpasteurised milk and contaminated water |
Listeria |
|
|---|---|
| Symptoms | Headache, fever, tiredness, aches and pains (symptoms and complications can be severe in some people) |
| How long it takes for symptoms to appear | 3 days to 10 weeks |
| How long symptoms last for | |
| Foods the infection is typically found in | Soft cheeses, unpasteurised milk, ready-to-eat deli meats |
E. coli |
|
|---|---|
| Symptoms | Diarrhoea (often bloody), abdominal cramps |
| How long it takes for symptoms to appear | Between 2 to 10 days |
| How long symptoms last for | About 1 week |
| Foods the infection is typically found in | Undercooked beef, unpasteurised milk and juice, sprouts and contaminated water |
Norovirus |
|
|---|---|
| Symptoms | Fever, nausea, vomiting, abdominal cramps, diarrhoea and headache |
| How long it takes for symptoms to appear | Between 24 to 48 hours |
| How long symptoms last for | 1 to 3 days |
| Foods the infection is typically found in | Undercooked shellfish, contaminated ready-to-eat foods |
Rotavirus |
|
|---|---|
| Symptoms | Severe gastro or flu-like symptoms |
| How long it takes for symptoms to appear | Between 24 to 48 hours |
| How long symptoms last for | Up to 8 days |
| Foods the infection is typically found in | Contaminated foods |
What causes food poisoning?
Food poisoning is caused by eating or drinking contaminated foods or drinks.
Food contamination can be caused by:
- not cooking foods properly
- not storing foods below 5°C
- someone who is unwell or has poor hygiene handling the food
- cross contamination — spreading germs between food, surfaces, utensils and equipment
You can read more about preparing food safely here.
What are high risk foods?
High risk foods include:
- meat —undercooked mince and rolled, formed or tenderised meats
- raw or undercooked poultry — chicken, duck and turkey
- raw or lightly cooked eggs
- cold meats —salami and hams
- seafood
- cooked rice or pasta — not kept at the correct temperature
- prepared salads — coleslaw, pasta salads, rice salads and fruit salad
- unpasteurised dairy products
When should I see my doctor?
Most cases of food poisoning don’t need medical attention.
You should see your doctor if you’re in a high-risk group (see below) and at risk of dehydration.
Also contact your doctor if you have any of the following:
- very severe symptoms
- not able to keep fluids down for more than a day
- symptoms for more than 3 days
- blood or mucus in your vomit
- blood or mucus in your stools (poo)
What are the high-risk groups for food poisoning?
People at greater risk of food poisoning are those who:
- are pregnant
- are elderly
- are very young
- have a weak immune system due to illness or medicines
Food poisoning can cause serious complications in these people.
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How is food poisoning diagnosed?
Your doctor will ask about your symptoms and examine you. They will ask about:
- foods you have eaten
- contact with other people who are unwell
- whether you have recently been travelling
Your doctor may recommend some tests, such as a stool (poo) sample to work out the cause. Sometimes blood tests are recommended.
It can be hard to diagnose food poisoning correctly. Finding the cause — the bacteria or virus — of food poisoning isn’t always possible.
How is food poisoning treated?
Most people don’t need medical help for food poisoning. You should stay home from work or school and drink plenty of fluids.
For a mild case of food poisoning, you can:
- suck ice chips — to replace lost fluids
- drink oral rehydration fluids — to replace lost electrolytes
Ease back into your normal diet and routine when you feel ready.
If possible, avoid preparing food at home while you’re unwell and for 2 days after your symptoms stop.
Antibiotics may help with some bacterial types of food poisoning, but aren’t usually needed.
Can food poisoning be prevented?
You can help prevent food poisoning by preparing food safely.
Always maintain good hand hygiene. Always wash your hands before preparing or eating food.
There are some vaccines that can help prevent severe food poisoning. Rotavirus vaccine is given to babies as part of their childhood vaccinations.
There are also other vaccines that may be recommended before travelling to some overseas countries. Talk to your doctor about food safety and travel vaccinations.
Foraged foods and wild mushrooms
Foraging for food is becoming increasingly popular in Australia. But when you gather wild plants and mushrooms, you can accidentally include toxic species.
Some wild mushrooms, including the death cap, are extremely poisonous. You shouldn’t eat foraged mushrooms unless you know that they are definitely safe.
If you suspect you have eaten poisonous mushrooms, call triple zero (000) for an ambulance.
Complications of food poisoning
Food poisoning can cause dehydration and can sometimes cause serious problems like kidney failure.
Sometimes people die from food poisoning.
Listeria food poisoning
Listeria food poisoning can be serious in vulnerable people, such as:
- people who are pregnant
- unborn and newborn babies
- older people
- people with a weakened immune system
It can cause sepsis or meningitis.
If you’re pregnant, listeria can lead to a miscarriage. This can happen even when you don’t know you’ve been infected. If you notice symptoms — usually like a mild flu but also diarrhoea, vomiting and nausea — contact your doctor immediately.
Resources and support
You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.