Has your frozen food gone bad?

Published: October 9, 2018

Frozen food packaged in a freezer Photo by Shutterstock/Yuliia Mazurkevych

Cottage freezers can be a tricky thing. Say, for instance, you’re away from the cottage for a while but decide to leave some frozen foods in there to lessen your next grocery load. How long does that food remain safe to eat? Here’s how you can determine whether or not the food in your freezer is still good.

Signs that food has gone bad

There are a few indications when a freezer either breaks down, or temporarily shuts off and then refreezes because of a power outage. You may begin to notice a new presence of unusual odours, a change in the food’s textures, and colours, and even seeing some food transform into frozen blocks.

But what actually happens to the food after it thaws and refreezes depends on how long your food is thawed for before refreezing. If it has only been a short period of time, the food could lose its natural texture. But after 1-2 days of being thawed, that’s when the odd odours may appear. In both cases, refreezing food can cause the food products to freeze into blocks, rather than individual frozen pieces, says Keith Warriner, a department of food science professor at Guelph University.

Think about peas.  In a normal frozen process, each pea should be frozen individually within the package. But if you find that there is a chunk of peas clumped together, this could be a sign that they’ve been refrozen.

Freezer burn is another common factor as to why food may go bad while in the freezer. Freezer burn occurs primarily when too much air reaches the products, which ends up drying them out and damaging them. This can easily be minimized by remembering to securely wrap your frozen food in airtight packing.

But how do you identify freezer burnt food? On meats like beef, what once was a bright red piece of beef, could now be covered in grey and brown spots — doesn’t sound too appealing. Though these meats can still be safe to eat, its taste will definitely be compromised.

The same goes for your delicious fruits and veggies. If your freezer was once filled with bright vegetables and fruits and are now replaced with dull and slimy ones, these foods will not taste as great as you know they should.  

Freezer food and power outage

During a power outage, the best thing to do is to keep the freezer closed, says Jeffrey Farber, director of the Canadian Research Institute for Food Safety. A full closed freezer should be able to keep the cold temperature for about two days, while a half-full freezer would keep its temperature for about one day. If you know the power is going to be out for a prolonged period of time, Farber recommends buying dry or block ice to keep the refrigerator as cold as possible.

If at any point the freezer temperature reaches to about 4 degrees celsius for more than two hours, you have now entered the danger zone, and should discard your food, specifically proteins including meats and fish says Farber.

Though foods spoil slower at lower temperatures, explains Warriner, bacteria will produce toxins that cannot be destroyed through cooking once the temperature rises to above 10 degrees celsius.

He says this is one risk of defrosting poultry on your kitchen counter, which becomes extremely relevant during Thanksgiving, when turkey is held at room temperature for an extended period of time before cooking and serving.

So, if there happens to be a power outage, and your freezer’s temperature rises at any point during the power outage (4 degrees celsius to be extra safe), then there’s a strong possibility that bacteria has already started to grow and even multiply.

In this case, many people may decide to purchase devices that monitor the temperatures of their refrigerators and freezers, while some may choose the more homey, and DIY methods.

The penny method

The penny method consists of filling a shot glass with water, letting it freeze, and then placing a penny on the top. When you return to your freezer and notice the penny is still sitting at the top, then it’s likely that there was no power outage long enough to raise the temperature, making your food still safe to consume.  

Warriner says this method makes sense, since if the ice is thawed, “then the penny drops — literally.” The only other consideration with this is if the temperature gets to 0 degrees celsius, making the penny drop. But in this instance, 0 degrees is not the major concerning temperature, which makes this technique not completely accurate. Farber also believes that the penny trick is not reliable.

So, the next time you’ve been away from your freezer for a while, you might want to examine your food before you decide to use it for your next meal. Try looking for signs of dark spots on your red meat, slimy and dullness in your fruits and veggies, formed chunks of frozen food, and even weird odours. You might also want to consider throwing a thermometer in along with your frozen food to get a more accurate reading. This might just help you avoid a trip to the doctors, or a night in bed for the rest of your cottage weekend.

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