I think it has more then historical reasons.
Of course
older fridges were not able to maintain an equal temperature
throughout
the whole box and to maintain a steady temperature at about the
set
temperature. Therefore a temperature had to be choosen that would
certainly
provide good storage condition with respect to sample (and
food)
deterioration and bacterial growth. At the same time, however, the
products
should not be frozen every time the fridge started a cooling cycle.
So the
set temp should be high enough above 0°C to prevent water-rich
fluids
(samples/food) from repeated freezing.
This is, I think, the
main reason for the 4°C limit
Dr. Dirk Bakkeren
clinical
chemist
Diaconessenhuis Eindhoven
Ds Th Fliednerstraat 1
5631 BM
Eindhoven
Nederland
