Reheating previously prepared dishes is a critical food safety point. Low temperatures mean bacterial growth and sick guests. In this article you'll learn step by step what you need to check to reheat safely.
Why reheating can be dangerous
Bacteria grow rapidly between 7°C and 63°C. We call this the danger zone. If you reheat dishes too slowly or at too low a temperature, you stay in this zone too long.
⚠️ Watch out:
Bacteria double every 20 minutes in the danger zone. After 2 hours there are already 64 times as many bacteria as at the start.
The core temperature rule
When reheating you must always reach a core temperature of 75°C. This applies to all previously prepared dishes, sauces and side dishes.
💡 Example:
You're reheating a stew from yesterday:
- Starting temperature from fridge: 4°C
- After 10 minutes reheating: 45°C (still dangerous)
- After 15 minutes: 75°C (safe)
Only then can you serve.
What you need to measure and check
Always use a core thermometer. Visual checks aren't enough. Even if a dish is bubbling on the outside, the core can still be cold.
- Insert the thermometer in the thickest part of the dish
- Measure in multiple places for large portions
- Wait 10 seconds for a stable reading
- Note the time you reach 75°C
Different reheating methods
Each method has its own points to watch:
💡 Example per method:
- Oven: Cover with foil, 160°C, check after 20 min
- Microwave: Stir halfway through, check multiple spots
- Stovetop: Stir regularly, medium heat
- Bain-marie: Slow but even, ideal for sauces
Time limits when reheating
The faster you reheat, the safer. Try to go from fridge to 75°C within 2 hours. Takes longer? Then the risk becomes too great.
⚠️ Watch out:
Large portions reheat more slowly. Divide into smaller portions for faster and safer reheating.
Registration and HACCP
Always note what you've checked. This is important for HACCP and during NVWA inspections.
- Reheating time: From when to when
- Core temperature reached: 75°C or higher
- Method used: Oven, microwave, stovetop
- Who checked: Name of staff member
💡 Example registration:
Date: 15-02-2025, 17:30
- Dish: Beef stew (2 liters)
- Reheating method: Oven 160°C
- Core temperature: 78°C reached at 17:45
- Checked by: Sarah K.
When not to reheat
Some dishes are better not reheated or are extra risky:
- Rice older than 24 hours: High risk of bacillus cereus
- Dishes already reheated once: Maximum 1 reheat
- Dishes with raw ingredients: Such as tartare or carpaccio
- Dairy-based sauces: Can curdle when reheated
With a digital HACCP system like KitchenNmbrs you can keep all your temperature measurements in one place, so you can find everything immediately during inspections.
How do you reheat safely? (step by step)
Check the starting situation
Check how long the dish has been in the fridge and at what temperature it was stored. Dishes older than 3 days or stored above 7°C are risky.
Choose the right reheating method
Divide large portions into smaller parts. Use oven for even heating, microwave for speed, or bain-marie for delicate sauces.
Measure the core temperature
Insert the thermometer in the thickest part and wait until you reach 75°C. Measure in multiple places for large portions. Note time and temperature.
Register and serve immediately
Note what you've checked for your HACCP records. Serve immediately after reheating or keep warm above 60°C.
✨ Pro tip
Only reheat what you need right away. Divide large portions into smaller parts - they reheat faster and safer than one large pan.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
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Frequently asked questions
Can I reheat dishes multiple times?
No, maximum 1 time. With each reheating round bacteria grow and risk increases. Only reheat what you're going to use right away.
How long can reheating take at most?
Try to go from fridge temperature to 75°C within 2 hours. Longer means too long in the danger zone between 7°C and 63°C.
Can I check the temperature without a thermometer?
No, visual checks aren't reliable. Even bubbling doesn't mean the core is 75°C. Always use a core thermometer.
What if my thermometer is broken?
Don't reheat then. A broken thermometer means you can't guarantee a safe temperature. Buy a new one immediately.
Do I have to register all of this?
Yes, temperature checks are mandatory for HACCP. Note at minimum time, temperature and who checked. This is important during NVWA inspections.
Which dishes are extra risky when reheating?
Rice dishes, poultry, ground meat and dishes with egg or dairy. These contain bacteria that grow quickly in the danger zone.
📚 Sources consulted
- EU Verordening 852/2004 — Levensmiddelenhygiëne (2004) — Official source
- EU Verordening 853/2004 — Hygiënevoorschriften voor levensmiddelen van dierlijke oorsprong (2004) — Official source
- EU Verordening 1169/2011 — Voedselinformatie aan consumenten (2011) — Official source
- NVWA — Hygiënecode voor de horeca (2024) — Official source
- NVWA — Allergenen in voedsel (2024) — Official source
- Codex Alimentarius — International Food Standards (2024) — Official source
- FSA — Safer food, better business (HACCP) (2024) — Official source
- BVL — Lebensmittelhygiene (HACCP) (2024) — Official source
- Warenwetbesluit Bereiding en behandeling van levensmiddelen (2024) — Official source
- WHO — Foodborne diseases estimates (2024) — Official source
Food Standards Agency (FSA) — https://www.food.gov.uk
The HACCP standards shown in this application are for informational purposes only. KitchenNmbrs does not guarantee that displayed values are current or complete. Always consult the FSA or your local authority for the latest regulations.
Written by
Jeffrey Smit
Founder & CEO of KitchenNmbrs
Jeffrey Smit built KitchenNmbrs from 8 years of hands-on experience as kitchen manager at 1NUL8 Group in Rotterdam. His mission: give every restaurant owner control over food cost.
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