Temperature Control
This domain tests the numbers. Questions ask you to identify the danger zone, choose a fridge or freezer setting, decide how long chilled food may be left out, or interpret a probe reading. Learn the figures and the reasoning behind each one, because examiners like a number plus a purpose.
The key temperatures
- Danger zone: 8 °C to 63 °C. Bacteria multiply fastest here; the optimum for most pathogens is around 37 °C. Some UK texts quote 5 °C to 63 °C, but the Food Standards Agency guidance uses 8 °C.
- Refrigeration: 0 °C to 5 °C. Check and record at least daily, ideally twice.
- Freezer: −18 °C or colder. Freezing prevents growth but does not kill organisms.
- Hot holding: 63 °C or above. Never reheat in a hot-holding unit.
- Cooking: 75 °C for 30 seconds at the centre or thickest part, or an equivalent such as 70 °C for 2 minutes, 65 °C for 10 minutes, or 60 °C for 45 minutes.
- Reheating: 82 °C for dishes that will be held hot.
- Cooling: 63 °C down to 8 °C within 90 minutes.
- Chilled food out of temperature control: no more than 4 hours in total, ideally a single period, then use or discard. The 2-hour/4-hour rule is the common restaurant formulation.
Monitoring
Use a probe thermometer that has been cleaned and disinfected before and after use, inserted into the thickest part. Probe between packs in a fridge, not against the back wall. Calibrate regularly using an ice-point check (0 °C) or boiling-point check. Record readings - records are your evidence of due diligence.
Worked example
A probe reading of 11 °C is taken from a fridge holding cooked ham first thing in the morning. Reasoning: 11 °C is inside the danger zone and above the 8 °C limit. Do not assume it was fine overnight. Move the stock to a working fridge, check the thermometer and the door seal, record the incident, and decide whether the ham is safe. A corrected 4-hour-plus excursion with no explanation usually means discard; brief, evidenced excursions within the 4-hour rule can be used immediately.
Traps that cost marks
- Saying the danger zone starts at 0 °C or 5 °C when the expected answer is 8 °C to 63 °C.
- Reheating to 63 °C instead of 82 °C.
- Confusing the cooking temperature (75 °C/30 s) with the reheating temperature (82 °C).
- Forgetting the 90-minute cooling window.
- Probing the fridge air gap rather than the food, or probing the surface rather than the centre.