Cooling cooked food safely is the discipline of moving hot food out of the danger zone — broadly 5°C to 63°C — quickly enough that bacterial spores cannot wake up, multiply and produce toxins. In UK food safety practice, the working rule is to cool cooked food from hot to chilled in no more than 90 minutes. Get it right and you protect customers; get it wrong and you create the perfect environment for Clostridium perfringens and Bacillus cereus, two of the commonest causes of UK food poisoning outbreaks linked to catering.
It is also the most-missed CCP in UK catering audits. If you have not yet mapped your CCPs, our guide to identifying critical control points is the natural starting point.
Why Cooling Matters More Than Cooking, Sometimes
Cooking destroys vegetative cells but spores survive. Once the food is sitting at, say, 45°C in a deep pan on the side, those spores germinate and the population doubles every 10 to 20 minutes. Clostridium perfringens specifically thrives in cooked meats, gravies and stocks held warm; Bacillus cereus is the rice and pasta one, but cooked vegetables and starchy sauces are vulnerable too. Both can be present after a perfectly safe cook because cooking does not eliminate spores.
The 90-Minute Rule in Practice
The rule is straightforward: food must cool from cooking to chilled storage temperature within 90 minutes. It is not the only safe regime — the FSA also recognises the more conservative 4-hour 60-to-21°C then 2-hour 21-to-5°C model used by larger manufacturers — but for catering, 90 minutes is the simple version EHOs expect to see if you say you cool food.
- Shallow containers: use 50 mm to 75 mm deep trays. A deep stockpot of chilli takes hours to cool no matter what you do.
- Increase surface area: portion large items before cooling. A whole turkey will not cool in 90 minutes; carved portions will.
- Move air across the food: use a blast chiller if you have one. If not, a clean cold area with a dedicated fan beats sitting on the side.
- Decant hot liquids: split into smaller volumes; stir occasionally; do not put the lid on until the food has cooled.
Blast Chilling: Worth Buying If You Cook in Advance
A blast chiller designed for commercial catering will bring a tray of cooked chilli from 80°C to 3°C in 60 to 90 minutes reliably — the rule the equipment was built for. If you regularly cook ahead, hold for events or run a banqueting operation, the cost works out fast when you compare it to a single Clostridium incident. For lower-volume kitchens, the same outcome is achievable with discipline: shallow trays, ice baths for soups and sauces, and someone whose job it is to watch the clock.
The Records the EHO Will Ask For
Cooling rarely gets you a red flag in real time; it gets you one when an outbreak investigation looks for the pattern. Your records need to show, for any cooked-and-cooled item, when it came off heat and when it reached chilled storage, plus the temperatures at start and end. Our HACCP template for restaurants includes a cooling log; pair it with the EHO inspection preparation guide so you know exactly what to have on hand.
Common Failures We See on Audits
- Cooked rice and pasta left at room temperature "until cool", then refrigerated overnight in deep tubs.
- Stocks and gravies sitting in 10-litre pans on the side because the pass needs the chiller space.
- Roasted joints wrapped tightly in foil while still steaming — the foil traps heat and slows cooling.
- Cooling logs filled in retrospectively at the end of the shift instead of when the timer goes off.
If any of these sound familiar, book a kitchen audit or run our free risk assessment — a 30-minute walkthrough finds these patterns before an outbreak does.
Train the Team on Why, Not Just How
Front-line staff follow rules they understand. A 10-minute briefing on what Clostridium does in a warm pan of bolognese changes behaviour in a way that a printed sign on the wall does not. Our Level 2 Food Safety and Hygiene course covers the microbiology in plain language and is the qualification EHOs look for on the file.
Frequently Asked Questions
Can I put hot food straight into the fridge?
In a small operation with a powerful chiller and a small portion of food, yes — and you should, because waiting at room temperature is exactly what the rule is trying to prevent. In larger volumes, putting hot food in a fridge warms the whole fridge, so a blast chiller or shallow-tray pre-cooling on a fan is safer.
What temperature counts as chilled?
UK law sets 8°C as the legal limit for chilled food storage. Most operators run fridges at 5°C or below as the practical target, leaving headroom for door openings.
Does the 90-minute rule apply to small portions?
Yes — but small portions in shallow trays make it easy. The rule is about getting through the danger zone fast; the smaller the mass and the bigger the surface area, the easier it is.
Written by Carren Amoli, BSc (Hons), RSPH Registered
