Method for virus clearance

1. A method for virus clearance of a cell culture medium, comprising the steps of:

i) providing a bulk medium portion, comprising amino acids and glucose;

ii) providing a first additive portion, comprising vitamins in aqueous solution;

iii) subjecting the bulk medium portion to a high temperature short time treatment (HTST);

iv) passing the first additive portion through a virus retentive ultrafilter, wherein or the virus retentive ultrafilter has a molecular weight (Mw) cut-off value below 100 kDa; and

v) after steps iii) and iv), mixing the bulk medium portion with the first additive portion to obtain a cell culture medium cleared from viruses.

2. The method of claim 1 , wherein step iii) comprises heating the bulk medium portion to a temperature of about 85-110° C., maintaining said temperature for about 1 s to about 10 min, and cooling the bulk medium portion to <40° C.

3. The method of claim 2 , wherein in step iii) the rate of heating is at least 5° C. per s.

4. The method of claim 2 , wherein in step iii) the rate of cooling is at least 5° C. per s.

5. The method of claim 2 , wherein the heating is performed in a flow-through heater.

6. The method of claim 5 , wherein the flow-through heater is an inductive heater.

7. The method of claim 2 , wherein the cooling is performed in a flow-through cooler.

8. The method of claim 1 , wherein the first additive portion comprises thiamine and/or pantothenic acid.

9. The method of claim 1 , wherein the bulk medium portion is passed through a sterilization-grade filter after step iii) and before step v).

10. The method of claim 1 , wherein after step v), the cell culture medium is passed through a sterilization-grade filter.

11. The method of claim 1 , further comprising the steps of:

providing a second additive portion, comprising one or more proteinaceous components;

subjecting the second additive portion to gamma or electron beam radiation; and

mixing the irradiated second additive portion with the bulk medium portion and the first additive portion to obtain a cell culture medium.

12. The method of claim 11 , wherein the proteinaceous components comprise serum.

13. The method of claim 11 , wherein the proteinaceous components comprise a protein hydrolysate.

14. A method of cultivating cells, comprising the steps as set forth in claim 1 and further comprising the steps of:

transferring the cell culture medium cleared from viruses to a bioreactor;

transferring cells to the bioreactor; and

cultivating the cells in the cell culture medium in the bioreactor.

15. The method of claim 14 , wherein the cells are animal cells.

16. The method of claim 14 , wherein the cells are microbial cells.

17. A method for virus clearance of a cell culture medium, comprising the steps of:

i) providing an amino acid portion, comprising amino acids, and a sugar portion, comprising glucose;

ii) providing a first additive portion, comprising vitamins in aqueous solution;

iii) subjecting the amino acid and sugar portions to a high temperature short time treatment (HTST);

iv) passing the first additive portion through a virus retentive ultrafilter, wherein the virus retentive ultrafilter has a molecular weight (Mw) cut-off value below 100 kDa; and

v) after steps iii) and iv), mixing the amino acid and sugar portions with the first additive portion to obtain a cell culture medium cleared from viruses.

18. The method of claim 17 , wherein step iii) comprises separately heating the amino acid and sugar portions to a temperature of about 85-110° C., maintaining said temperature for about 1 s to about 10 min, and cooling the amino acid and sugar portions to <40° C.

19. The method of claim 17 , wherein the first additive portion comprises thiamine and/or pantothenic acid.

20. The method of claim 18 , wherein the heating is performed in a flow-through heater and the cooling is performed in a flow-through cooler.