Hello,

I have been growing both adherent and suspension cell cultures from 2 years. Recently a problem has occurred. Cells started developing background, not bacterial or fungal since the media is not turning turbid. I have attached the images of MDA MB-231 cells. But the same kind of background is being observed in other cell lines as well (HEK 293T, HCT116). It is slowing the growth of the cells.

I use DMEM(HyClone) media with 10% FBS(South American origin HyClone) and L-Glutamine along with Antibiotic/antimycotics. The incubator and Culture hood have been recently fumigated. The CO2 is maintained at 5%.

Kindly help me identify where the problem lies.