Fetal Bovine Serum, United States Origin. Collected at government approved abattoirs in the United States. True pooled and triple 0.1 micron sterile filtered that passes sterility, mycoplasma, and 9CFR viral testing requirements. Dialyzed by tangential flow filtration (10,000 MW cut-off) against saline solution to remove small molecules such as amino acids, hormones and cytokines while avoiding the precipitation of serum proteins.