Reheat leftovers until steaming hot all the way through, and only reheat them once.
Requirement — Food safety (microbiological)
Reheat leftovers until steaming hot all the way through, and only reheat them once.
Target: 70°C in the thickest part, or an equivalent from the table below.
How to tell, without a thermometer
- Steam rising from the centre, not just the edges
- The middle is hot to the touch, tested after removing it from the appliance
If it has not got there: Keep going, and break dense food up or spread it out so the heat can reach the middle. If it will not heat through evenly, a microwave to get the centre hot followed by the air fryer to crisp the surface is a better tool for the job than the air fryer alone.
Important: Cooked rice and pasta left at room temperature can develop Bacillus cereus toxins that reheating does not destroy. If cooked rice has been out of the fridge for more than an hour, discard it rather than reheating it.
| Temperature | Held for | Measured at |
|---|---|---|
| 70°C | 2 min | the centre of the food |
| 75°C | 30 sec | the centre of the food |
Why this is the rule
Reheating is not cooking and it asks a different question. The food has already met a cooking standard once; what matters now is whether it has spent time in the range where bacteria multiply, and whether reheating takes it back out of that range quickly and completely. An air fryer is good at this for anything that should be crisp and poor at it for anything dense, because the surface reaches temperature long before the middle does — which is exactly the failure mode that makes reheating riskier than it looks. It is worth noting that at least one manufacturer's hardware agrees: the Reheat programme on the Instant machines has a lower temperature ceiling than the cooking programmes, so the appliance itself refuses to treat reheating as cooking.
When it applies
This rule governs food in these states: Leftover (reheating).
This outranks any cooking time on this site. Where a cooking recommendation cannot be reconciled with a rule like this one, AirfryerHQ does not publish the recommendation — not with a warning attached, not greyed out, not at all.
Evidence and confidence
- Applies to
- Applies generally
- Why this rating
- Both halves are now passage-verified from two separate FSA publications: the reheating standard from one, the cooling and storage conditions that make it meaningful from the other.
- Last reviewed
- 2026-08-13
What this does not cover
- The rice and pasta escalation above is a specific hazard with a specific mechanism, and this general rule does not substitute for it.
- Neither source addresses reheating IN AN AIR FRYER specifically. The observation that surface heats faster than centre in this appliance class is AirfryerHQ's, and it is a reason to be more careful rather than a modification of the standard.
Sources (2)
Food Standards Agency — UK food-safety authority (United Kingdom (England, Wales and Northern Ireland))
Relied on for: That leftovers should only ever be reheated once, and that food should be steaming hot throughout.
States this directly
Passage read and verified
Retrieved 2026-08-13 from gov.uk
How to chill, freeze and defrost food safely
Food Standards Agency — UK food-safety authority (United Kingdom (England, Wales and Northern Ireland))
Relied on for: The cooling window before refrigeration and the once-only reheating position after refreezing.
States this directly
Passage read and verified
Retrieved 2026-08-13 from gov.uk