Power outages are common during Australian summers, raising concerns about food safety. Knowing how long your fridge and freezer can preserve food during blackouts can help avoid health risks and unnecessary waste.
How Long Can Food Stay Safe Without Power?
Food microbiologist Tom Ross from the University of Tasmania advises discarding perishable food if the power has been out for more than four hours. If your fridge stays above 5°C for over four hours, the food becomes unsafe.
Food safety scientist Rozita Vaskoska from CSIRO suggests keeping a thermometer in the fridge for accurate temperature checks. If the power returns within two hours and the fridge temperature stays under 5°C, the food should remain safe. If it exceeds 5°C for more than four hours, discard the food to avoid foodborne illnesses.
The Food Safety Information Council states a fully stocked freezer can keep food chilled for up to 48 hours with the door shut, while a half-full freezer lasts around 24 hours.
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Which Foods Are Most at Risk?
Vaskoska categorises “potentially hazardous foods” as those that rely on low temperatures to prevent microbial growth. These include:
- Raw or cooked meat and eggs
- Seafood
- Soft cheeses
- Cooked foods like rice and pasta
Other high-risk items include dips, pâté, and ham. Foods like yoghurt, pickles, and jams, which have high acidity or sugar content, last longer in warmer conditions. However, once refrigeration is compromised, their shelf life reduces.
Ross warns that smallgoods, such as cured meats, typically last for several weeks in refrigeration but spoil faster when exposed to higher temperatures.
When to Discard Food?
If the power outage exceeds four hours, perishable foods stored above 5°C should be discarded. Food stored at unsafe temperatures can lead to foodborne illnesses, causing vomiting, diarrhoea, and stomach discomfort.
The risk increases for vulnerable groups, including children, the elderly, pregnant women, and immunocompromised individuals. If food develops an unusual smell, slimy texture, or odd appearance, discard it immediately.
How to Keep Food Safe During a Blackout?
Taking preventive steps can help minimise food waste during power outages.
- Limit Opening the Fridge and Freezer:
Minimise door openings to keep cold air inside. Ross explains that the temperature rise is slower in colder climates but faster in warmer regions. - Use Alternative Cold Storage:
Consider transferring food to a neighbour’s or friend’s fridge or using an esky with ice packs. - Keep Food in the Freezer:
A full freezer retains cold longer than a half-full one. Ensure the freezer door stays shut as much as possible. - Monitor Room Temperature:
In hot climates, food safety risks increase rapidly. Err on the side of caution and discard questionable items.
Can You Refreeze Thawed Food?
The Food Safety Information Council states that food partly defrosted but still below 5°C can be refrozen, though the quality might decline. Refreezing affects texture and water retention but does not pose a health risk if the temperature remains low.
However, if the freezer warms to room temperature, refreezing becomes unsafe due to bacterial growth.
Handling Food Safety in Extended Power Outages
During severe weather events, power can be out for extended periods. On a recent Wednesday night, Ausgrid reported 120,000 customers without power across Sydney, the Hunter, and the Central Coast. Essential Energy reported 30,000 outages across regional NSW, while Endeavour Energy had 25,695 customers affected.
In such situations:
- Keep fridge and freezer doors closed as much as possible.
- Use portable coolers with ice packs if available.
- Seek alternative refrigeration options with friends, neighbours, or community centres.
Final Tip: When in Doubt, Throw It Out
If you’re unsure how long food has been stored above 5°C, the safest choice is to discard it. Foodborne illnesses can be severe, especially for vulnerable individuals. Prioritise safety and avoid unnecessary health risks during power outages.
