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Seven in ten fridges found to contain harmful bacteria

Infrequent cleaning and unsafe fridge temperatures put us at risk

A glut of harmful bacteria that could make you ill is thriving in the majority of fridges, a new Which? investigation reveals.

We analysed 10 fridges and found cause for concern in seven of them.In the most serious cases, we uncovered high levels of Aeromonas bacteria, which is associated with warmer temperatures and can cause food-borne illness and a range of infections, from skin conditions to sepsis.

Not keeping your fridge at the right temperature and not cleaning it frequently enough are two of the main reasons why harmful bacteria thrive. That's why we assess temperature stability and ease of cleaning as part of our tough tests.

See our full list of Best Buy fridge freezers.

Fridge germ testing: what we found

We took five swabs from 10 different fridges. In each one, we took a sample from the vegetable drawer, the bottom shelf (where meat should be kept), the upper door rack, the back wall and the outer door handle - as the image below shows.

You introduce new microbes into the fridge every time you unpack groceries, so we weren't surprised to find that every fridge was teeming with bacteria.

In many cases they were harmless, but we were concerned by 19 of the 50 samples we collected. As well as the two samples of Aeromonas bacteria, we also found worrying concentrations of Enterobactera clocae and Klebsiella oxytoca, among others.

These germs are linked with respiratory and urinary infections, especially for people with existing health problems or weakened immune systems. They're likely to have come from unwashed vegetables, highlighting the importance of cleaning your fridge regularly.

Finding the right fridge temperature

Harmful pathogens can multiply rapidly in warmer temperatures. Yet half of us don't know that a fridge needs to be kept between 0°C and 5°C, according to the Food Standards Agency.

Even if you did know the correct fridge temperature, there's a good chance the temperature in your fridge isn't what you think it is.

More than four in ten of the fridge freezers we've tested have a default or recommended setting that's either inaccurate or unreliable. And many more struggle to maintain a safe and stable temperature when it's hot or cold in your kitchen.

Find out how to keep your food fresher for longer.

How to clean a fridge in six simple steps

  1. Don't wait until spilt milk or soggy spinach forces your hand. Instead, clean your fridge around once a month and, if needed, defrost the freezer at the same time.
  2. Cleaning the fridge will push the internal temperature up, so the best time to do it is before a big shop when the fridge is fairly empty.
  3. After removing the food, take all the shelves, drawers and door racks out of the fridge and wash them in warm soapy water.
  4. Wipe down the inside of the fridge with lukewarm soapy water. Make sure the water isn't too hot and try to minimise the amount of time the fridge door is open as both will send the fridge temperature soaring.
  5. Using anti-bacterial spray in your fridge isn't recommended as it could get on to your food.
  6. A mixture of water and baking soda is effective at removing stubborn stains, while a small cup of baking soda placed in the fridge will help to absorb odours over time.

Our fridge freezer cleaning tests

We spray cherry juice into every fridge we test, letting it drip down into cracks and crevices and turn into a sticky mess.

We then assess how easy it is to clean. The worst have few removable parts and lots of nooks and crannies capable of harbouring stray crumbs.

Compare how easy it is to clean different models using our fridge freezer reviews.