If you've lost power in a blackout, it can be difficult to figure out which foods can be preserved.
Wondering how long your fridge will stay cool enough to store food if you've lost power, or what should be binned and what can be salvaged? Here's what two experts have to say.
How long without power is too long for your food during a blackout?
Tom Ross, a specialist in food microbiology at the University of Tasmania, says general advice is to discard perishable food after the power has been out for more than four hours.
Dr Ross says In some instances, such as severe weather, you may be eligible for compensation (from your energy distributor or insurance) if there's an outage, but this is often only if your power has been out for longer than eight hours.
Food safety scientist at Australia's national research body the CSIRO, Rozita Vaskoska, says the concerns are mainly around perishable or "potentially hazardous food" (more on this below).
"In an ideal scenario, people have at-home thermometers to check the temperature of the fridge or the temperature of the food."
Dr Vaskoska says if the fridge's temperature exceeds 5 degrees Celsius for less than two hours and the power returns, it should be OK.
Or, you can find alternative refrigeration (by putting food in an icy esky) at or before the two-hour mark to avoid the food potentially spoiling.
Dr Vaskoska says if food is stored at a temperature higher than 5C for more than four hours "you need to throw it out".
According to the Food Safety Information Council "if the freezer door is kept shut, a full freezer can keep food chilled for up to 48 hours, while a half-full freezer can keep food chilled for 24 hours".
What are 'potentially hazardous' and perishable foods?
Dr Vaskoska says what she calls "potentially hazardous foods" are "temperature dependent in terms of their safety and the growth of microorganisms in them".
According to Dr Vaskoska and Dr Ross, these foods often include or contain:
- raw or cooked meat
- raw or cooked eggs
- seafood
- soft cheeses
- cooked foods such as cooked rice cooked pasta.
On the other hand, Dr Vaskoska says "things like yoghurt that are very acidic, or pickles, or some sorts of jams that have high sugar, they can sustain a little bit more".
Dr Ross says smallgood products such as cured meats often "have a shelf life of three or four weeks under refrigeration conditions".
"Now the refrigeration's gone then they're more rapidly becoming less safe."
Anything with a foul smell, or slimy or unusual texture, is probably better off binned.
"Even though food that has been exposed to higher temperature might seem OK, that exposure to higher temperature also means that the overall shelf life is now reduced."
Dr Vaskoska says the reason why these foods shouldn't be eaten once they've been stored at more than 5C for four hours or more is "because it can lead to foodborne illness".
"Foodborne illness is anything that includes symptoms such as diarrhoea or vomiting. Anything that comes from the gastrointestinal tract."
Dr Ross says the average person would be "sick for a few days" with foodborne gastroenteritis, but " young, old, pregnant, and immunocompromised people [are] at greater risk of particular kinds [from] smallgoods and soft cheeses".
Consider the climate and keep fridge doors closed
Dr Ross says rules such as "throw away perishable food once you've been without power for more than four hours" are helpful but don't necessarily take your individual circumstances into account.
He says the temperature of a fridge and freezer is going to rise slowly in a Tasmanian winter, compared to a Queensland summer.
In warm weather it's best to err on the side of caution, he says.
Dr Vaskoska and Dr Ross recommend limiting opening the fridge and freezer as much as possible, to help it stay cooler for longer.
"The colder the temperature, the longer the food will last," Dr Ross says.
Also, "minimise the time that the food stays out of the fridge".
Consider quality and taste (as well as safety)
The Food Safety Information Council says "foods that have partly defrosted or defrosted but remain very cold (5°C or less) can be refrozen."
Dr Vaskoska says that "In normal circumstances refreezing only leads to quality issues."
"It's a bit of a commonsense decision," she says, "if you have meat defrosting and refreezing it will only affect the quality, mostly around the water holding."
However, if the freezer had reached and stayed at room temperature for a long time "it would represent a health risk".
This is general information only. For detailed personal advice, you should see a qualified medical practitioner who knows your medical history.
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