The Times Australia
The Times World News

.

Here's why your freezer smells so bad – and what you can do about it

  • Written by Enzo Palombo, Professor of Microbiology, Swinburne University of Technology
Here's why your freezer smells so bad – and what you can do about it

Most people would expect a freezer can keep perishable food fresh and safe from spoilage for many months. Unfortunately, this is not always the case.

Have you ever noticed a funky smell in your freezer? Where does it come from and what can be done to fix the problem?

Hardy microbes and pungent chemicals

There are several causes for bad smells coming from your freezer. Typically, the culprits are microbes – bacteria, yeasts and moulds.

Although a freezer dramatically slows down the growth of most common spoilage microbes, some can still thrive if the temperature rises above -18℃ (the recommended freezer temperature[1]). This can happen if there is a power outage for more than a few hours, or if you put something hot straight in the freezer.

Food spills and open containers provide an opportunity for microbes to get to work. It’s also worth noting that many microbes will survive freezing[2] and start growing again once conditions are favourable – for example, if you remove the food, partially thaw it, and return it to the freezer.

Two things happen when food breaks down. First, as microbes start to grow, several pungent chemicals are produced. Second, the fats and flavours that are part of the food itself can and will be released.

These are generally referred to as volatile organic compounds (VOCs). They are the pleasant aromas that we sense when we eat, but VOCs can also be produced by bacteria.

For example, many of us would be familiar with the smells that come from fermentation – a microbial process. When fermenting a food, we intentionally contaminate it with microbes of known characteristics, or provide conditions that favour the growth of desirable microbes and subsequent production of aromatic compounds.

By contrast, uncontrolled food spoilage is problematic, especially when the contaminating microbes can cause disease.

Close-up of chopsticks picking up a piece of kimchi from a white bowl
Kimchi is one of the foods we deliberately allow to be ‘contaminated’ in order to produce the intense flavour. Nungning20/Shutterstock

Freezing changes the food

It is not only microbial growth that can lead to undesirable odours. There’s a suite of chemical processes happening in the freezer, too.

Freezing causes physical changes to foods, often enhancing their breakdown. Many of us would be familiar with “freezer burn” on meats and other foods, as well as ice crystals on frozen food.

This phenomenon is called “salt rejection[3]”. Depending on how rapidly something is frozen, salts can sometimes be concentrated, as pure water freezes at a higher temperature than water with things dissolved in it – like sugars and salts. On a large scale, this happens to icebergs in the ocean. As the sea water freezes, salt is removed. Thus, the iceberg is composed of fresh water, and the surrounding sea water becomes a saltier and denser brine.

In a similar way, as water in food freezes, organic molecules are concentrated and expelled. If these are volatile, they move about the freezer and stick to other things. Where they end up depends on what else is around.

Some of the volatiles like water. We call them “hydrophilic” or water loving; those are the ones that will make your food taste bad. Other are more water-hating or “hydrophobic” and they stick to things like silicone ice cube trays, making them go smelly[4].

Domestic freezers are commonly attached to a refrigerator, and this provides another opportunity for smells to move through the systems. The two units share a single cooling source and airflow channel. If your fridge has foul odours from the food inside (natural or after microbial spoilage), it is very likely they will migrate to your freezer.

Read more: How colour-coding your fridge can stop your greens going to waste[5]

Help, my freezer smells!

There are some simple steps you can take to stop your freezer from smelling.

First, try to prevent odours from developing in the first place by covering the food. If you place food in an airtight container (glass is best), it will dramatically slow the release of any aromatic compounds produced by bacteria or the food itself. Covered food is also less likely to absorb smells and flavours from other foods around it.

If the smells have already developed, you can eliminate them by following a few simple steps, including a thorough clean.

  • Remove all items from the freezer and inspect the foods for any spoilage, freezer burn or unpleasant odours.

  • Discard anything that has developed ice crystals and store the rest in a cooler box while attending to the freezer itself. You should also inspect the fridge and discard any bad-smelling foods.

  • Once you have removed all items, take out the shelves and clean up spills or crumbs.

  • Wipe down all surfaces using warm soapy water or a mix of two tablespoons of baking soda with warm water.

  • Wash all the shelves and ice compartments and let them dry completely.

If the smells are not removed with these simple cleaning steps, the freezer may require a deep clean, which involves turning off the unit and letting it “breathe” for a few days.

Placing some baking soda inside the freezer before adding food can help to absorb any residual odours. For serious smells where crevices or insulation are contaminated, you may need a service technician.

In short, even though we think freezers keep things “fresh”, microbes can still proliferate in there. Make sure to clean your freezer now and then to keep your food safe and healthy.

References

  1. ^ the recommended freezer temperature (www.foodsafety.asn.au)
  2. ^ survive freezing (www.safefood.qld.gov.au)
  3. ^ salt rejection (en.wikipedia.org)
  4. ^ making them go smelly (www.nytimes.com)
  5. ^ How colour-coding your fridge can stop your greens going to waste (theconversation.com)

Read more https://theconversation.com/heres-why-your-freezer-smells-so-bad-and-what-you-can-do-about-it-203058

Times Magazine

Building an AI-First Culture in Your Company

AI isn't just something to think about anymore - it's becoming part of how we live and work, whether we like it or not. At the office, it definitely helps us move faster. But here's the thing: just using tools like ChatGPT or plugging AI into your wo...

Data Management Isn't Just About Tech—Here’s Why It’s a Human Problem Too

Photo by Kevin Kuby Manuel O. Diaz Jr.We live in a world drowning in data. Every click, swipe, medical scan, and financial transaction generates information, so much that managing it all has become one of the biggest challenges of our digital age. Bu...

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

The Times Features

Is our mental health determined by where we live – or is it the other way round? New research sheds more light

Ever felt like where you live is having an impact on your mental health? Turns out, you’re not imagining things. Our new analysis[1] of eight years of data from the New Zeal...

Going Off the Beaten Path? Here's How to Power Up Without the Grid

There’s something incredibly freeing about heading off the beaten path. No traffic, no crowded campsites, no glowing screens in every direction — just you, the landscape, and the...

West HQ is bringing in a season of culinary celebration this July

Western Sydney’s leading entertainment and lifestyle precinct is bringing the fire this July and not just in the kitchen. From $29 lobster feasts and award-winning Asian banque...

What Endo Took and What It Gave Me

From pain to purpose: how one woman turned endometriosis into a movement After years of misdiagnosis, hormone chaos, and major surgery, Jo Barry was done being dismissed. What beg...

Why Parents Must Break the Silence on Money and Start Teaching Financial Skills at Home

Australia’s financial literacy rates are in decline, and our kids are paying the price. Certified Money Coach and Financial Educator Sandra McGuire, who has over 20 years’ exp...

Australia’s Grill’d Transforms Operations with Qlik

Boosting Burgers and Business Clean, connected data powers real-time insights, smarter staffing, and standout customer experiences Sydney, Australia, 14 July 2025 – Qlik®, a g...