Fetal Bovine Serum is derived from the blood of fetuses of slaughtered dams which have passed ante and post mortem veterinary inspection in government supervised slaughter-houses and are passed as fit for human consumption. The blood is obtained by cardiac puncture utilising a single-use needle, tube and bag. The blood is allowed to clot naturally and is then centrifuged to obtain the liquid fraction of the blood which is now regarded as semi-processed serum. No other additions or deletions of material are permitted. STERILE FILTERED: Semi-processed Raw Fetal Bovine Serum, is thawed, pooled and filtered through a series of sterile membranes down to 0.1 microns before being finally packaged, usually in 500ml or 1L bottles. No further processing, additions or deletions are performed. However, subsequent treatment, including gamma irradiation or heat inactivation, may be carried out and the bottles labelled accordingly.