Marika Day: A complete guide to freezing food and reducing food waste

ARTICLE

1 April 2024

4 mins read

Short on time? Low on groceries? AIA Eat Well ambassador and Accredited Practising Dietitian Marika Day explains how to prepare, protect, and store leftovers in the freezer so you’ll always have nutritious meals ready to heat.

Freezing leftovers can be an easy and convenient way to save money, save time on busy days, and reduce your household’s food waste. In fact, across the food supply chain, Australians throw away an average of 312kg of food per person each year¹ – and even with the rising cost of living, research shows that 64.2% of us dump food in the bin each week because we don’t use it².

But the humble household freezer can help. By knowing how to portion leftovers, protect food from freezer burn, and keep track of shelf life, you can plan to have a variety of simple, healthy meals at your fingertips, even when you’re home late or out of time to pop to the shops.

Here are my tips for freezing leftovers.

First, check the temperature

To be food safe, you should store frozen food at –15°C or colder.

You might have heard of the food ‘danger zone’ – the temperature range in which bacteria can grow easily. This zone is between 5°C and 60°C, so your freezer (and your fridge) should be safely below it. If you experience an emergency power outage, food in the freezer should be able to stay frozen for up to 48 hours – but open the freezer door as little possible to preserve the cold.

Use appropriate containers

Choose freezer-safe, airtight containers or bags to store your frozen food. They should be leakproof, not brittle, resistant to moisture vapour, easy to seal, and easy to label. Containers that aren’t meant for the freezer – like regular glass jars, plastic bags, or cardboard cartons – may crack, leak, or absorb freezer moisture and odours.

Why not cut down on your plastic usage with silicone food storage bags, or tempered glass containers: they’re not porous, they don’t contain petrochemicals, and they’re transparent so you can see what meals you’ve stored with a quick glance. Some tempered glass containers can even go straight from the freezer into the oven or microwave once you’ve thawed the food (and then into the dishwasher).

And if you’re strapped for room, square containers are more space-efficient than round containers.

Freeze in small portions

Food freezes quicker and thaws easier when it’s in smaller portions (and flattened evenly), so divide your leftovers into meal sizes, in separate containers, before you put them in the freezer. This also helps reduce food waste, because you can thaw only the portion you want to eat instead of having to defrost an entire large container’s worth of food.

It’s also important to leave about 3cm of space at the top of the container or bag to allow the food to expand as it freezes.

And again, to stay food safe, try to get leftovers portioned and in the freezer within two hours of cooking.

Protect from freezer burn

There’s nothing worse than pulling a yummy dinner out of the freezer only to discover that it’s lost its moisture, flavour, and texture. While freezer burn doesn’t make food unsafe to eat, it can make it really unpleasant. Some foods, like fruits, vegetables, and bread, are more susceptible to freezer burn than others. And even when they’re sealed in airtight containers, many foods are likely to lose their quality if they’re left in the freezer for too long³.

Avoid freezer burn by placing foods that are more susceptible to freezer burn in airtight bags or containers, rather than leaving them in plastic or paper bread bags or cardboard cartons. Let any excess air out of freezer-safe bags before sealing them, and let hot food cool down before freezing so steam doesn’t get sealed in.

Be mindful of shelf life

While frozen food can stay top quality in the freezer for months, it’s a good idea to keep track of how long each item has been stored – and use it within the recommended storage time – to make sure it’s yummy and safe to eat.

Different foods have different shelf lives in the freezer, and frozen cooked meals typically have a recommended storage life of three to four months⁴. But if you open the container and notice any bad smells, err on the side of caution and throw it out.

Label and date everything

To help yourself keep track of shelf life, label and date each container or bag with the name of the food, the date it was frozen, and any cooking instructions. This will help you easily see what you have in the freezer and make sure that you use the oldest items first.

Avoid the defrost-refreeze cycle

You might have heard that it’s unsafe to refreeze food once it’s been defrosted, and that’s partly true. Harmful bacteria can grow in food that has been completely thawed to the ‘danger zone’ (above 5°C).

Avoid this by defrosting your leftovers in the fridge, not out on the bench – and keep them cold in the fridge until you’re ready to cook. Then, you can safely refreeze any unused portion that has defrosted in the fridge. (Just be aware that this cycle will likely reduce its quality: research has shown that some thawed-then-refrozen meat can lose colour, juiciness, and even nutritional value⁵.)

But if your frozen food has thawed to room temperature, defrosted in the microwave, or been out of the fridge for more than two hours, do not refreeze it – to stay food safe, throw any leftovers away.

With just a little planning and food safety know-how, you can fill your freezer with a huge variety of nutritious, budget-friendly meals, save time, and cut down your food waste by extending the life of your ingredients.

Footnotes

¹ https://www.dcceew.gov.au/environment/protection/waste/food-waste

² https://www.comparethemarket.com.au/news/how-much-food-australians-dump-2023/

³ https://extension.umn.edu/preserving-and-preparing/science-freezing-foods

⁴ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/freezing-and-food-safety

⁵ https://pubmed.ncbi.nlm.nih.gov/35670479/

Marika Day

Marika Day is an Accredited Practising Dietitian and Nutritionist with over 10 years' experience in a variety of clinical and non-clinical areas. Her expertise and interests include gastrointestinal nutrition, which is influenced by her personal experience with coeliac disease. Additionally, she focuses on women’s health and the complexities of disordered and emotional eating. In addition to her clinical expertise, Marika regularly works in recipe development, helping people make nutritious choices every day. Her approach to nutrition is balanced, practical and empathetic and aims to help people enjoy food and live a healthy balanced life.

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