"Food poisoning" is the illness that results from eating contaminated food. Knowing the common culprits, how they spread and who is most at risk helps you understand why each rule in this course exists.
What foodborne illness looks like
Symptoms commonly include nausea, vomiting, stomach cramps, diarrhoea, fever and headache. They can appear within hours or take several days, which is why people often blame 'the last thing they ate' when the real cause was a meal a day or two earlier.
Most healthy adults recover in a few days, but the same illness can cause severe dehydration, hospitalisation or death in vulnerable people. Some pathogens also cause long-term complications such as reactive arthritis or kidney failure.
Common bacteria and viruses in Australia
A small group of micro-organisms causes most of Australia's foodborne illness. You do not need to be a microbiologist, but it helps to recognise them and the foods they favour:
- Salmonella — raw poultry, eggs and egg products; a leading cause of illness in Australia
- Campylobacter — raw and undercooked chicken; one of the most common causes overall
- Listeria monocytogenes — grows even in the fridge; dangerous in pregnancy (deli meats, soft cheese, pre-cut salads, smoked seafood)
- E. coli (including Shiga-toxin types) — undercooked mince, unpasteurised milk, contaminated produce
- Staphylococcus aureus — spread from hands, skin and nose to ready-to-eat food; produces a toxin
- Clostridium perfringens and Bacillus cereus — large batches of cooked food and rice held in the danger zone
- Norovirus and Hepatitis A — viruses spread by infected food handlers, often via unwashed hands
People most at risk
Some customers are far more likely to become seriously ill from unsafe food. Take extra care whenever you prepare food for these groups:
- Pregnant women and their unborn babies (especially the risk from Listeria)
- Babies and young children
- Older adults, particularly in aged care
- People with weakened immune systems, including cancer, diabetes and organ-transplant patients
Practical examples
- Reheating a large batch of rice that sat out for hours can cause Bacillus cereus poisoning.
- A pregnant customer is advised to avoid pre-made deli salads partly because of Listeria.
- A food handler with norovirus who skips handwashing can infect dozens of customers.
Key points to remember
- Symptoms can appear hours or days after the contaminated meal.
- Salmonella, Campylobacter and Listeria are major Australian concerns.
- Listeria is unusual because it can grow at fridge temperatures.
- Vulnerable groups can become seriously ill from small amounts of contamination.