How you thaw, cook, cool and reheat food decides whether bacteria are killed or given the chance to multiply. Each step has a safe method — and a risky shortcut to avoid.
Thawing frozen food
Thawing on the bench lets the outside of the food sit in the danger zone for hours while the centre is still frozen. Thaw safely instead:
- Thaw in the fridge (5°C or below) — the safest method, though it takes time
- Thaw in a microwave only if you cook the food immediately afterwards
- Thaw as part of the cooking process for some foods
- Make sure food is fully thawed before cooking so it cooks evenly, and never refreeze thawed potentially hazardous food
Cooking thoroughly
Cooking kills most harmful bacteria if food reaches a high enough core temperature. As a guide, cook potentially hazardous food until the centre reaches 75°C, and check with a clean probe in the thickest part.
Take particular care with higher-risk foods. Poultry, mince, sausages, rolled roasts and stuffed meats must be cooked right through — pink chicken or raw mince in the centre is a real hazard.
Cooling cooked food safely
Cooked food left to cool slowly spends hours in the danger zone. Australian guidance sets a two-stage cooling target you should aim to meet:
- Cool from 60°C down to 21°C within 2 hours
- Then cool from 21°C down to 5°C within the next 4 hours
- Speed cooling by dividing food into smaller, shallow portions
- Use an ice bath or blast chiller, and stir liquids like soups and sauces
- Never put large amounts of hot food straight into the fridge — it warms everything around it
Reheating
When reheating previously cooked food for hot holding, heat it quickly and all the way through — reach at least 60°C, and commonly 75°C in the centre, moving through the danger zone fast.
Reheat food only once. If reheated food is not used, throw it out rather than cooling and reheating it again.
Practical examples
- A frozen chicken is moved to the fridge the day before to thaw safely.
- A big pot of bolognese is split into shallow trays and cooled in an ice bath to meet the 2-hour/4-hour cooling targets.
- Leftover soup is reheated rapidly to 75°C once; any that is left over is discarded.
Key points to remember
- Thaw in the fridge, not on the bench; never refreeze thawed hazardous food.
- Cook potentially hazardous food to about 75°C in the centre.
- Cool 60→21°C within 2 hours, then 21→5°C within 4 more hours.
- Reheat rapidly to at least 60°C and reheat only once.