Why it's worth cleaning your forgotten freezer and how to do it simply

The freezer can be "the last frontier" of kitchen cleaning — a forgotten wasteland, where food goes to die.But it's important to do a clean-out semi-regularly, although perhaps not for the reason you'd expect.Associate Professor Julian Cox, a food microbiologist and safety expert from UNSW who works on the traditional lands of the Bidjigal people at Kensington in Sydney, says cleaning your freezer is less about hygiene and food safety and more about food quality.And it's essential for keeping the appliance running efficiently.When meals are stored promptly in the freezer in sealed, airtight containers, the food-safety risk is low. (Pexels: Iara Melo)Why cleaning out your freezer is importantDr Cox, who is also the Food Safety Information Council's scientific director, says if food is well packaged in tightly sealed containers before being put into the freezer, "safety is probably not an immediate concern".All living things need water to thrive, he says, and bacteria can't access the frozen water in food in a freezer.However, he says doing a regular audit of your freezer's contents can help you stay across what's inside it, so you can eat the food before its quality declines.Dr Cox says domestic freezers freeze food slowly, which creates large ice crystals that can disrupt the food's structure and texture.Foods with a high water content, such as vegetables, tend to lose quality more quickly in the freezer. (Unsplash: Bozhin Karaivanov)"The general advice would be foods that are higher in moisture (for example, fruit and vegetables) will last less than foods that are high in fat and protein (such as grated cheese)," he says.For this reason, Food Safety Information Council CEO Lydia Bachmann recommends labelling food in the freezer with the date it went in."Put a sticker on it and … use the oldest things first, just to make sure you're not wasting food," she says.Wayne Cochran owns an appliance repair business on Ngunnawal and Ngambri country in Canberra, and is an electrician and fridge mechanic by trade.He says doing a regular clean-out of your freezer is also important so it doesn't become overpacked, which can prevent it from operating properly."The modern-day freezer creates the cold air in the back and circulates it," he says."That air can't circulate properly if your freezer's packed too heavily … you'll find the food at the front of the freezer starts going off and getting soft."How often does a freezer need cleaning?A freezer with food that's been packaged properly "shouldn't need doing too often", Ms Bachmann says.However, Jason Shipway, who owns a professional cleaning business based in Goomburrup/Bunbury in Western Australia, says as a general rule, home freezers should get a "good deep clean maybe once or twice a year"."And then every few months, just give it a quick surface wipe and get rid of built-up frost."Most newer freezers are "frost-free" and should not become coated in ice. (Unsplash: Kindel Media)How to defrost a freezerIf you're doing a proper freezer clean, you may need to do a defrost beforehand.Mr Cochran says the modern "frost-free" freezer contains a heater that turns on every eight to 12 hours, and this melts any frost that has formed on the evaporator that creates the appliance's cold air.The sweet spot for frost in any freezer is 5 millimetres or less, Jason Shipway says. (Unsplash: S. Laiba Ali)"If you're getting frost in a newer style freezer, there's something wrong with it," he says.The exception to this rule occurs in regions with high humidity."Up north in Queensland … they get frost in them all the time because there's so much humidity in the air that every time you open it, you fill it up with moist air, and it just can't keep up," Mr Cochran says.But he says older freezers, typically the "cyclic-defrost" variety, don't defrost themselves and will need a manual defrost no matter where you are located.In terms of how much frost is OK, Mr Shipway says 5 millimetres or less "is the sweet spot"."You want to make sure it's not really building up because then it's just going to throw everything out of whack," he says."The freezer is going to be working harder to keep everything cool."A thick layer of ice will stop your freezer from working efficiently. (Unsplash: Dev Benjamin)He says the best way to defrost a freezer is to turn off the appliance and place some bowls of hot water inside to speed up the melting process.Mr Cochran says it's not a good idea to pick at the ice with a sharp instrument "because you'll just damage the freezer".Before you turn the freezer off, Ms Bachmann recommends emptying the contents into your fridge, where the food should stay frozen while you do your defrost and clean.Dr Cox says storing the food in an insulated shopping bag with some ice bricks will also do the job.If your fridge and freezer use the same power source, once you turn it off, make sure you keep the fridge door closed to keep the cool air inside.Jason Shipway owns a cleaning business that operates in Bunbury and Perth in Western Australia. (Supplied: Enhanced Cleaning)Cleaning a freezer and what to useMs Bachmann and Mr Shipway say once your freezer is defrosted, wiping it out with a solution of bicarb soda and water is the best way to clean it.Mr Shipway recommends a teaspoon of bicarb in a small spray bottle of water.Dr Cox says bicarb is a "tried and true" option that will do the job."If you're really wanting to give it that extra clean or … sanitary treatment, you could use some dilute, working-strength … cleaning bleach," he says, adding that whatever you use, it must be appropriate for kitchen surfaces."Then maybe giving it a further rinse down afterwards, then make sure that it's been well dried," he says.Cleaning your freezer's seals with soapy water and checking for splits is also worth doing, Mr Cochran says."If they don't seal properly [due to splits] … that will make it slightly inefficient but it will also cause a frost build up," he says.He also recommends cleaning dust from the condenser, which is usually found behind or under the freezer."If it chokes up with dust … you can't get rid of the heat," Mr Cochran says."So, a six-monthly blowout or vacuum of the condenser is never a bad thing."