Freezer Temperature Check: How to Complete This Daily Food Safety Check

Why freezer temperature checks matter

Freezing food at -18°C or below stops bacterial growth completely. Unlike refrigeration, which only slows bacteria down, proper freezing puts bacteria into a dormant state. They cannot multiply, produce toxins, or cause food to spoil.

However, freezing does not kill bacteria. If food thaws and reaches temperatures above 8°C, any bacteria present will start growing again. This is why maintaining consistent freezer temperatures is critical.

Beyond food safety, temperature fluctuations damage food quality. Ice crystals form inside food cells, and repeated freezing and thawing causes these crystals to grow larger, damaging texture and flavour. Consistent freezing preserves quality as well as safety.

Legal requirements

Food safety regulations require frozen food to be kept at -18°C or below. While there is no specific law mandating freezer temperature checks, your food safety management system must demonstrate that you maintain safe storage conditions.

Environmental Health Officers will expect to see evidence of temperature monitoring. If your freezer has been running too warm and you have no records, you cannot prove your frozen food is safe.

Target temperatures

Freezer Type	Target	Maximum
General storage	-18°C to -22°C	-18°C
Blast freezer (during use)	-30°C to -40°C	-18°C after cycle
Display freezer	-18°C to -20°C	-18°C

The -18°C limit is an international standard adopted across the UK, EU, and most other countries. Some businesses aim for -20°C or below to provide a safety margin.

Ice cream and some delicate products may have specific storage requirements from the manufacturer. Always check product labels for storage instructions.

When to complete this check

Minimum frequency

Check freezer temperatures at least once daily, typically at the start of the day. Freezers are more stable than fridges because the door is opened less frequently and the thermal mass of frozen food helps maintain temperature.

Additional checks

You should also check freezer temperatures:

After deliveries - When adding large quantities of frozen stock
After power outages - Even brief outages can affect temperature
If ice build-up is excessive - This can indicate a problem with the door seal or defrost cycle
If food appears thawed or soft - Trust your observations and verify with a check
After defrosting - Confirm the freezer returns to safe temperature before restocking

How to complete the check

Step 1: Check the display or use a thermometer

Unlike fridges, freezer built-in displays are generally reliable because they measure air temperature and frozen food temperatures are very similar. You can use the digital display for routine checks.

However, for verification or if you suspect a problem, use a probe thermometer. Insert it between frozen packs or use an air probe.

Step 2: Take the reading

If using the built-in display, simply read and record the temperature shown.

If using a probe thermometer:

Insert the probe between frozen packs in the centre of the freezer
For air temperature, hold the probe in the middle of the freezer space
Wait for the reading to stabilise (this takes longer in freezers due to the cold)
Note that probes can be slow to respond at very low temperatures

Step 3: Record the temperature

Record the temperature in your monitoring system. In Pilla, you will enter the number into the temperature field. If you have multiple freezers, make sure you record against the correct unit.

Step 4: Check it is within range

Your reading should be -18°C or below. If it is above -18°C, investigate immediately.

What to do when temperature is wrong

Temperature between -15°C and -18°C

This is a warning sign. The freezer is running warm but food is still frozen:

Check the door seal is intact and closing properly
Check nothing is blocking the door from closing fully
Check ice build-up is not preventing a good seal
Check the freezer is not overloaded with recent deliveries
Re-check the temperature in 2-4 hours
If still above -18°C, call for maintenance

Temperature above -15°C

This requires immediate action:

Check the food - Is it still frozen solid? Are there ice crystals throughout?
Check the cause - Is the compressor running? Is the door closing? Has power been interrupted?
Move high-value stock to another freezer if available
Do not add new stock until the problem is resolved
Document everything - Record what happened and what action you took

Assessing partially thawed food

If freezer temperature has risen significantly, you need to assess each product:

Safe to keep:

Food is still frozen solid with no soft spots
Ice crystals are visible throughout the product
Temperature at the centre is still well below 0°C

Must be discarded:

Food has thawed completely
No ice crystals remain
Product is soft or liquid
Food has been above 8°C for more than 4 hours

May be cooked and used immediately:

Food is partially thawed but still cold (below 8°C)
Cook thoroughly and serve immediately
Do not refreeze

The no-refreeze rule

Never refreeze food that has thawed unless it has been cooked first. Refreezing damages quality and, more importantly, bacteria may have multiplied while the food was thawed. Freezing again does not kill these bacteria.

The exception: if food has thawed but remained below 5°C and was thawed for less than 24 hours, some guidance permits refreezing. However, the safest approach is to cook thawed food or discard it.

Common mistakes to avoid

Ignoring ice build-up

Excessive frost or ice inside the freezer is not just an inconvenience. It indicates that warm, moist air is getting in, usually through a faulty door seal. This warm air raises the temperature and the moisture freezes on surfaces. Fix the cause, do not just scrape off the ice.

Overloading after deliveries

Adding large quantities of unfrozen or partially thawed delivery stock raises the freezer temperature. Spread large deliveries across multiple freezers if possible, or allow extra time for the temperature to recover before recording your check.

Not checking all freezers

Large kitchens may have multiple freezers in different locations. Check every unit, not just the ones that are convenient. A freezer in a back corridor or basement is just as important as the one in the main kitchen.

Assuming frozen means safe

Just because food is frozen does not mean it is safe to use. Frozen food can still become unsafe if:

It was contaminated before freezing
It has been stored too long (beyond its shelf life)
It has been thawed and refrozen
The freezer has failed in the past and you have no records

Blocking air circulation

Freezers need air to circulate to maintain even temperatures. Packing products too tightly or blocking vents creates warm spots where food may not freeze properly.

Multiple freezers

Most commercial kitchens have more than one freezer. You need to check each unit separately.

Label your freezers clearly and consistently. Common naming includes:

Location-based: Kitchen Freezer, Store Room Freezer, Prep Area Freezer
Number-based: Freezer 1, Freezer 2, Freezer 3
Purpose-based: Meat Freezer, Fish Freezer, Ice Cream Freezer

In Pilla, create separate checks for each freezer so you can track temperature history for each unit individually.

Consider the contents of each freezer:

High-value stock - Check more frequently and ensure backup options
Long-term storage - These freezers may be opened less often but still need monitoring
Display freezers - Often run warmer due to glass doors, may need different targets

Equipment maintenance

Regular maintenance

Defrost when needed - Follow manufacturer guidance, usually when ice build-up exceeds 5mm
Clean door seals - Wipe seals regularly to remove debris that prevents a good seal
Check seal integrity - Place a piece of paper in the closed door; if it pulls out easily, the seal needs replacing
Clean condenser coils - Dust and grease reduce efficiency
Keep the area around the freezer clear - Allow air circulation for the condenser

Warning signs of failure

Temperature gradually rising over days or weeks
Compressor running constantly
Unusual noises from the motor
Excessive ice build-up despite good door seals
Food in the centre not freezing properly

Address these signs before complete failure occurs. A freezer full of stock is expensive to lose.

Summary

Freezer temperature checks protect your frozen stock investment and ensure food safety. While freezers are generally more stable than fridges, regular monitoring catches problems before they become costly failures.

Remember:

Target -18°C or below
Check at least once daily
Never refreeze thawed food
Act quickly if temperature rises
Record every reading

Freezer Temperature Check: How to Complete This Daily Food Safety Check

Key Takeaways