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Why doesn't all food stay fresher in the fridge? © iStock

Why doesn't all food stay fresher in the fridge?

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The low temperatures of our refrigerators slow down bacteria reproduction & other food-spoiling reactions, but sometimes the cold can accelerate these effects.

Asked by: Robin Tucker, Exeter


In general, low temperatures will slow bacterial reproduction and the chemical reactions associated with spoilage. But for some foods, other processes are accelerated. For example, the cell membranes in banana skin become unstable at low temperatures and release the enzyme polyphenyl oxidase, which makes them turn black. Also, bread goes stale faster at 4°C, because of complex reactions between amylose, amylopectin, gluten and water.


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Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


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