Quick-frozen food must be kept at −18 °C or colder, with brief rises to −15 °C allowed in transport and to −12 °C in retail cabinets. Stores and vehicles must have recording instruments to EN 12830, and the recordings must be kept for at least a year. Other frozen food has no fixed figure in law, so −18 °C is good practice rather than a rule.
Why it matters
Frozen is the one place the law asks for a recorder
Frozen food feels low risk: it is hard, it is cold and nothing grows. But a cold store holds weeks of stock in one room, a failed compressor is noticed only when someone walks in, and product that has partly thawed and refrozen can look fine. The rules reflect that.
Quick-frozen food is the only area of UK food law that fixes a storage temperature, its tolerances, the type of recording instrument and how long to keep the recordings. If you run a cold store, a frozen distribution depot or a frozen vehicle fleet, those rules apply to you whatever your certification standard says.
What the rules say
−18 °C and the two tolerances
Schedule 2 to the Quick-frozen Foodstuffs (England) Regulations 2007 requires quick-frozen food to reach '–18oC or colder' after thermal stabilisation and then be 'maintained at a level no warmer than –18oC'. There are two exceptions: 'brief periods during transport (including local distribution)' when it may be warmer than −18 °C 'but not warmer than -15oC', and a retail display cabinet, where it may be warmer 'to an extent consistent with good storage practice but not warmer than -12oC'. Wales, Scotland and Northern Ireland have the same figures.
Monitoring is set by Commission Regulation (EC) No 37/2005. Transport, warehousing and storage must be fitted with 'suitable recording instruments to monitor, at frequent and regular intervals, the air temperature'. The instruments must comply with EN 12830, EN 13485 and EN 13486, and 'temperature recording shall be dated and stored by the food operator for a period of at least one year, or for a longer period taking into account the nature and the shelf life'. What those three standards cover is explained on our EN 12830 page.
Retail is lighter. Article 3 says retail display cabinets and local distribution need only 'at least one easily visible thermometer', read at the air return side at the load line in open cabinets, and the England Regulations exempt retail cold stores under 10 m³ that use a visible thermometer.
- Storage: −18 °C or colder
From Schedule 2 to the Quick-frozen Foodstuffs (England) Regulations 2007. The −15 °C transport limit is for brief periods only; −12 °C applies only in retail display cabinets.
Other frozen food, fish, ATP and Ireland
Food that is frozen but not sold as quick-frozen has no statutory −18 °C. SFBB for retailers calls −18 °C 'good practice', which is what most customers and auditors expect. Regulation 853/2004 sets 'not more than −18 °C in all parts of the product' for frozen fishery products, with 'short upward fluctuations of not more than 3 °C' in transport, and −18 °C for frozen minced meat (Annex III).
For international journeys the ATP agreement sets −20 °C for ice cream, −18 °C for quick-frozen food and −12 °C for other frozen food, and allows 'a brief rise of the temperature of the surface of the foodstuffs of not more than 3 °C in a part of the load' during defrosting. In Ireland, S.I. 290/1992 and S.I. 370/1995 set the same −18 °C rule and one-year record, with 3 °C tolerances in transport and in retail, so an Irish retail cabinet may reach −15 °C, not the UK's −12 °C.
What good looks like
A cold store an auditor can read in five minutes
Start with the instrument. Ask your monitoring supplier for the EN 12830 conformity documents and keep them, because 37/2005 asks you to. An annual UKAS-accredited calibration across the working range meets the periodic verification EN 13486 describes, in our view (EN 13486 is licensed; we paraphrase). Calibrate at at least three points that bracket the operating range and the alarm set points (for a +2 °C to +8 °C fridge, for example 0, 5 and 10 °C), to ±0.5 °C; our UKAS laboratory (No. 10723) covers −35 to +40 °C in its air chamber for whole loggers and sensors, and −90 to +135 °C in a dry block for probes. Then decide the logging interval yourself, because 'frequent and regular' is not defined, and set retention to at least a year beyond the longest shelf life you store.
Alarm on what the law cares about, not on every defrost. Air in a cold store swings during evaporator defrost, and ATP's own allowance shows that a brief surface rise is expected. The Cold Chain Federation is exploring higher set points such as −15 °C for energy, but that does not change the law for quick-frozen food or your customer's specification.
Worked example
A defrost that does not finish
This is an illustrative example; times and readings are invented. A third-party cold store runs at −22 °C with defrosts every six hours, which normally recover in 25 minutes. Its alert fires when the air has been warmer than −18 °C for 40 minutes (recovery plus 15), and its action alarm when the air has been warmer than −15 °C for 15 minutes.
Saturday 02:00, a defrost starts and the air passes −18 °C at 02:10, as it does on every defrost. The heater contactor sticks, so the air does not recover. 02:50, the alert fires and the shift lead acknowledges it. The air passes −15 °C at 02:52 and the action alarm reaches the on-call engineer at 03:07. 03:35, the engineer isolates the heater and the room starts to pull down. 05:30, air is back below −18 °C.
What the store does: downloads the record, probes product between packs near the evaporator and the door, and finds the warmest surface at −16 °C. It tells the product owners, records the event and lets each owner decide on release against their specification. What changes: a second high-temperature alarm on defrost termination, and the heater contactor added to the maintenance schedule.
Where it is unclear
"Brief", "frequent" and non-quick-frozen stock
The law never defines how long a 'brief period' at up to −15 °C may last, or how often 'frequent and regular' recording must be. ATP's defrost allowance is also not given in minutes. Food that is frozen but not labelled quick-frozen falls back on the general HACCP duty, so its limit is a business decision. Our positions are under −18 °C and its tolerances.
The editions of the standards also differ: ATP cites EN 13486:2002 while BSI now lists the 2023 edition. Ask your supplier which edition its verification or calibration follows and keep the answer with the certificates.
Inspection findings
What officers look at
The FSA's Practice Guidance for officers starts with air temperature records, which it says 'are an indication of temperature history, including defrost cycles, door openings and breakdowns', then moves to between-pack readings with a total tolerance of +2.8 °C, and to destructive product testing for formal action. A store with credible records and a calibrated instrument can end the check at the first stage.
Under the 2007 Regulations, failing to keep the recording is an offence and records must be shown to an authorised officer on request. We found no published national data on frozen storage findings; the Hillingdon prosecution, where a walk-in freezer was 'sounding an alarm displaying a temperature of 30 degrees Celsius', shows the kind of temperature finding that ends up in a prosecution file.
In summary
The short version
- Quick-frozen food: −18 °C or colder, brief transport rises to −15 °C, retail cabinets to −12 °C.
- Stores and vehicles for quick-frozen food need EN 12830 recorders and at least one year of dated records.
- Retail cabinets and small retail cold stores may use a visible thermometer instead.
- Other frozen food has no statutory figure; −18 °C is good practice and what customers expect.
- A cold store has no tolerance: alert when the air stays warmer than −18 °C beyond the measured defrost recovery, and keep the defrost data behind the delay.
- Ireland has the same −18 °C rule and one-year record, but its retail cabinet tolerance is 3 °C (−15 °C), not the UK's −12 °C.