Regardless of whether you’ve got a serum free or an animal source free media, you still have the potential for adventitious agents as part of the cell line. And so, my understanding of the viral removal requirements would be that you would need two different methods for viral removal. Part of the reason for that is you want to have the back up, and part of it is using different means. Often you don’t have one single method that achieves the level of viral removal that you’re looking for. So you may have one step that’s using a low pH, you may have another one that’s solvent- detergent treatment step. There are some instances where the column chromatography is used, as removal can be achieved by physical means. There’s a lot of good background and explanation of this entire concept in ICH Q5A.
