1. Biological contamination
Living organisms getting into food: bacteria such as Salmonella, Listeria, Campylobacter and E. coli, plus viruses like norovirus and hepatitis A, moulds and parasites. This is the type behind most reported food poisoning in Australia, and the one the bulk of your training addresses.
You prevent it with temperature control, thorough cooking, handwashing, keeping raw and ready-to-eat food apart, and staying away from food when you're sick.
This comes up on the test — and the training that covers it is free to read.
Start the Free Training2. Chemical contamination
Chemicals ending up where they shouldn't — cleaning product sprayed near an open food container, sanitiser not rinsed off a preparation surface, pest bait stored above dry goods, or acidic food left in an unsuitable metal container long enough to leach.
The controls are mostly about storage and labelling: keep chemicals in their original labelled containers, store them well away from and below food, and follow the contact and rinse times on the label.
3. Physical contamination
Objects in food. Glass from a broken container, metal from a damaged scourer or a chipped tin, plastic from packaging, a fingernail, a bandage, jewellery, hair, or a piece of bone or stone that came in with the ingredients.
Prevention is practical: no jewellery beyond a plain band, hair tied back or covered, no glass near open food where it can be avoided, and a proper procedure when something breaks — clear the area, dispose of any food that could have been reached, and clean thoroughly before restarting.
4. Allergenic contamination
An allergen reaching a customer who has to avoid it — usually through cross-contact rather than an ingredient list. A shared knife, a shared fryer, a spoon moved between containers, or flour dust settling on a plated meal is enough to trigger a reaction in someone who is genuinely allergic.
It's listed separately from biological and chemical contamination because it behaves differently: the amount can be tiny, cooking doesn't remove it, and the consequences for one specific customer can be immediate and severe. Australia declares a specific list of allergens that must be identified, including peanuts, tree nuts, milk, eggs, fish, crustacea, molluscs, sesame, soy, lupin, wheat and other gluten-containing cereals, plus added sulphites above the threshold.