Heat inactivation occurs when serum is heated to 56°C for a period of 30 minutes.
Here's a protocol for heat inactivation:
1. Allow serum containers to come to room temperature. Swirl bottles of serum immediately before adding to the water bath.
2. A water-filled control bottles (T1) should be placed in a 56 °C water bath. Place the containers in the water bath up to the serum line. Do not completely submerge the containers. When the temperature of T1 reaches 56 °C, start the timer set for 30 minutes. Do not allow temperatures to exceed 56 °C. Higher temperatures will denature the proteins, gel the serum or alter the performance of the serum.
3. Gently swirl the bottles every 5 to 10 minutes while in the water bath and check the temperature in the control bottle. It is not uncommon for plastic containers to bow slightly after heat treatment. This is not harmful to the serum.
4. At the end of 30 minutes remove the serum bottles from the water bath. Aliquot the serum into smaller volumes and freeze. Sigma-Aldrich does not recommend repeated thaw-freeze cycles.