Blood circulating in our bodies is warm. Donated blood is kept cold or frozen. Why? Is it because donated blood loses freshness because it’s not being circulated?
(I googled around and found information on temperature and storage, but nothing about why donated blood is stored cold.)
It’s stored cold for at least two reasons:
Less chance of (bacterial) infection with low temperature
Better preservation of the red blood cells (and various plasma proteins) if stored cold
Basically, this is pretty much the reason that we store most things at low temperature.
As an aside, blood, and plasma, can be stored frozen. Doing so preserves all the vital proteins which would otherwise deteriorate even at, say, 4 degrees centigrade (refridgerator temperature). However, it’s costly and cumbersome and only used to store plasma (not the red blood cells themselves)
Thank you. 
That seemed right, but I wanted to complicate things by thinking about circulation.