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.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.