A mammalian cell culture medium would typically have very many different components including proteins such as hormones and other growth factors, plant hydrolysates, animal serum etc.

Media with components of animal origin are widely used to grow common cell lines such as CHO and NSO, and can have contaminants such as mycoplasmas and endotoxins which pose a significant problem.

Mycoplasmas can have a ruinous effect on mammalian cells as they can alter every cellular parameter resulting in unreliable data which consequently can compromise the safety of the biological products.

Endotoxins from bacterial cell walls, in significant concentrations, can have a detrimental effect on growth of mammalin cells.

Thus, final sterilization grade filtration to remove bacteria and mycoplasma is very important to media preparation for mammalian cell cultures.

Pre-filtration which can take care of particulate and colloidal contamination is required to enhance the throughput from the final filter.