How to avoid food poisoning

Food poisoning affects an estimated 4.1 million people in Australia every year. The symptoms of food poisoning can range from mild to severe, but there are steps you can take to reduce your risk, says Jean Hailes dietitian Stephanie Pirotta.

Food poisoning is caused by bacteria, toxins or viruses present in the food or drinks we consume. In Australia, food poisoning is commonly due to bacteria, namely the Campylobacter or Salmonella bacteria types.

However, as Ms Pirotta explains, not all bacteria are bad for you; some bacteria in food is normal – and in some cases, such as the good bacteria found in yoghurts, it can even be beneficial.

"Bacteria becomes a problem and can cause food poisoning when they grow to unsafe levels, or if the type of bacteria present in the food is harmful," says Ms Pirotta.

Symptoms of food poisoning may include nausea (feeling sick), vomiting, stomach pains, diarrhoea (loose watery bowel motions), feeling weak, headache, fever, chills or sweating. When the symptoms start, how long they last and how serious they are can depend on many factors.

A common assumption is that food poisoning is caused by the last thing the person ate. However, this is often not the case, says Ms Pirotta. "Symptoms of the bacteria Campylobacter food poisoning [one of the most common culprits] usually develop two to five days after eating the food," she says. And which food is usually the guilty party in cases of Campylobacter? "This type of illness is frequently associated with eating undercooked chicken," says Ms Pirotta.

So how can you best protect yourself? Below Ms Pirotta answers some frequently asked questions.

What are some potentially 'high risk' foods of food poisoning?

Many people know that chicken or fish are common sources of food poisoning, but there are other common foods that can be potentially dangerous. Sources of food poisoning will usually look, smell and taste normal, so in this way it can be hard to detect.

Some potentially high-risk foods include:

raw and cooked meat (including red meat, chicken, turkey and seafood) and foods containing these, such as a casserole or curry
eggs and foods containing eggs, such as omelette or quiche
dairy products and foods containing these, such as custard or cheesecake
deli meats and smallgoods, such as ham or salami
cooked rice and pasta
prepared foods, such as coleslaw, pasta salad, rice salad, fruit salad and other ready-to-eat foods such as a sandwich/roll/leftover pizza that contain foods listed above
opened pre-packaged foods (can, carton or plastic container/bag), especially foods not refrigerated straight after they are opened.

What is the 'temperature danger zone'?

This is the temperature range in which harmful bacteria can grow to unsafe levels in food. The danger zone is between 5⁰C and 60⁰C.

This means it is best to keep cold foods cold – in your fridge, set below 5⁰C – and hot food should be kept and served hot – at 60°C or hotter. Using a food thermometer is an easy way to measure food temperature. These can be bought at most supermarkets.

For freshly cooked food that you're not going to eat straight away, the Australian Food Safety Information Council advises to cool them to below the danger zone as quickly as possible: divide food into small shallow containers and place in the fridge or freezer as soon as it stops steaming.

How do you know if a food has been out of the fridge too long, if it can be put back in, or when it should be thrown away?

The '2 hour/4 hour rule' tells you how long potentially high risk foods can be safely held at temperatures in the danger zone – for example leaving the food outside the fridge, after cooking or at the table.

If the food has been in the danger zone for two hours or less, it is generally considered safe to eat OR to put back in the fridge to eat later.
If the food has been in the danger zone for 2-4 hours, it is generally considered safe to eat straight away (not stored for later).
If the food has been in the danger zone for four hours or more, it may be unsafe to eat and should be thrown away.

What's the deal with cooked rice?

Many people are unaware that cooked rice, when improperly stored, is a common source of food poisoning. Cooked rice is a perfect growing ground for bacteria as it is moist, full of carbohydrates for energy and provides heat. Rice grains often contain the bacteria Bacillus cereus. These bacteria can form spores that are able to survive the high temperatures of cooking. If uneaten rice is cooled slowly and left in the temperature danger zone for too long, tiny spores can grow and produce a harmful toxin (poison).

This also means reheating the cooked rice does not kill the spores or destroy the toxins that have already been produced in the rice, so they can still make you ill.

Food poisoning symptoms from this bacteria and its toxins usually consists of vomiting and/or diarrhoea for up to 24 hours.

What are some other tips we can practise at home to avoid food poisoning?

When cooking or preparing food, try to prevent food or food surfaces coming into contact with other parts of your body or your clothing (also, wear clean clothing when cooking)
Cover any cuts or abrasions on your body
When preparing food, wash your hands using warm water and soap before you start, as well as:
- after going to the toilet (ensure you remove any aprons prior to going)
- after touching other body parts and coughing, sneezing, smoking, blowing your nose, eating
- before handling ready-to-eat food (such as salad)
- after touching raw foods (such as meat)
Use different utensils/ chopping boards for ready-to-eat foods and raw meats
Do not prepare food if you are ill or experiencing diarrhoea and/or vomiting
When buying food, ensure that the food packaging seal is unbroken, within its use-by date and that the can is not dented.

Food can be a celebration and bring great joy as well as healthy nutrition to your life and body. Let's keep it that way by following Ms Pirotta's advice. Find out more about good nutrition.