Food Safety Temperature Control: The Numbers That Matter
Temperature is the single most powerful tool a food handler has against harmful bacteria. Get the numbers right and most food poisoning risks simply never get the chance to develop.
Most cases of food poisoning come down to one thing: food spending too long at the wrong temperature. Harmful bacteria thrive in warmth, and they multiply quickly when food is left in the range that suits them. The reassuring flip side is that careful temperature control is one of the most reliable ways to keep food safe — and the rules behind it are genuinely simple to learn.
The danger zone
The most important concept in temperature control is the danger zone: the range of temperatures in which harmful bacteria multiply most rapidly. According to the MPI Simply Safe & Suitable template this is 5°C to 60°C. The aim of almost every temperature control measure is to keep food out of this range, or to move it through the range as quickly as possible when that cannot be avoided.
Put simply, cold food should be kept genuinely cold, and hot food should be kept genuinely hot. The trouble starts when food drifts into the lukewarm middle and stays there.
Keep it cold, keep it hot, or don't keep it at all. Food lingering in the danger zone is food turning into a hazard.
Chilling: keeping cold food cold
Cold storage slows bacterial growth dramatically. Chilled food should be held at a safe refrigeration temperature — typically 5°C or below — to keep it out of the danger zone. Good chilling practice includes:
- Setting refrigerators to maintain a safe temperature and checking them regularly.
- Not overloading fridges, so cold air can circulate properly.
- Cooling cooked food intended for chilling as quickly as possible before refrigerating.
- Keeping high-risk foods covered and stored to prevent cross-contamination.
Cooking: destroying bacteria with heat
Thorough cooking is what actually kills harmful bacteria in raw foods. Check the core — the thickest part of the item, where heat penetrates last. For poultry, minced meat and liver, the MPI template accepts 75°C for 30 seconds, 70°C for 3 minutes or 65°C for 15 minutes.
A clean, calibrated probe thermometer is the only reliable way to confirm this. Judging by colour or texture alone is guesswork, and guesswork is exactly what temperature control is designed to remove. This step is so important that it is often a critical control point in a HACCP plan.
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Hot holding and reheating
Once food is cooked, keeping it hot matters just as much as cooking it properly. Under the MPI Simply Safe & Suitable template, hot food must be kept above 60°C and checked with a calibrated thermometer. If a check finds food below 60°C, reheat it to above 75°C and raise the hot-cabinet setting; food held below 60°C for more than 4 hours must be thrown away. When food is reheated, heat it until steaming hot, at least 75°C, measured in the coolest part of liquids or the middle of solids, then keep it above 60°C. Bain-maries and hot cabinets keep food warm; they do not reheat it.
A common mistake is reheating food only until it feels warm. Surface warmth is not enough — the heat must reach the centre. As a rule, food should be reheated only once and then either served or safely discarded.
Cooling cooked food safely
Cooling is one of the most overlooked steps. The two-stage cooling benchmark is: cool from 60°C to 21°C within 2 hours, then from 21°C to 5°C or below within a further 4 hours. Food that does not reach 5°C within 6 hours in total should be thrown away. Practical methods include dividing food into smaller portions, using shallow containers, and not stacking hot food into a fridge before it has begun to cool.
Your legal duty
Temperature control is not just best practice — it underpins the legal duty to produce safe food. Under the Food Act 2014 and your Food Control Plan, food businesses must maintain the cold chain and avoid temperatures that could result in a risk to health, as part of a HACCP-based food safety system overseen by the Ministry for Primary Industries (MPI).
🔑 Key takeaways
- The danger zone is 5°C to 60°C — keep food out of it whenever possible.
- Chill cold food to 5°C or below; hold hot food at 60°C or above.
- Cook food until the core reaches a safe temperature, commonly 75°C; use a clean probe.
- Reheat until steaming hot, at least 75°C, then hold above 60°C.
- Cool cooked food using the two-stage rule (60°C to 21°C in 2 hours, then to 5°C in 4 hours), and remember temperature control is a legal duty under the Food Act 2014 and your Food Control Plan.
Master a handful of key temperatures and you have mastered the core of food safety. With consistent chilling, cooking, hot holding and cooling — and a habit of checking with a probe — New Zealand food businesses can prevent the vast majority of food poisoning risks before they ever begin.
