Temperature shift

is a decrease in temperature to values of between 28 °C and 35 °C which is executed in the production of many antibodies after reaching the desired cell density. This protracts the apoptosis (programmed cell death) and allows an increase in the antibody production of 50 % to 200 %. While the shift between temperatures of 30 °C to 35 °C is realised in the middle of the  logarithmic growth phase, shifts to lower temperatures are generally conducted in the initial stationary growth phase. See fed-batch processes.