Why does food rot? © Getty Images

Why does food rot?

Refrigerator companies must be pretty grateful for this bit of biochemistry.

Asked by: Jacob Hipkiss, Southwell

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As cells die, their membranes degrade and enzymes start leaking out. The cell digests itself, then neighbouring cells, and the process cascades. Without any immune response to stop them, bacteria and fungi will also begin eating the food and multiplying. As they munch away, they alter the texture of the food and release waste products that change the taste. There are purely chemical rotting mechanisms too, like fat oxidation, which makes it taste rancid.


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