Fetal bovine serum

Fetal bovine serum (FBS) or fetal calf serum (spelled foetal in Commonwealth English) is the blood fraction remaining after the natural coagulation of blood, followed by centrifugation to remove any remaining red blood cells. Fetal bovine serum comes from the blood drawn from a bovine fetus via a closed system of collection at the slaughterhouse. Fetal bovine serum is the most widely used serum-supplement for the in vitro cell culture of eukaryotic cells. This is due to it having a very low level of antibodies and containing more growth factors, allowing for versatility in many different cell culture applications.

The globular protein, bovine serum albumin (BSA), is a major component of fetal bovine serum. The rich variety of proteins in fetal bovine serum maintains cultured cells in a medium in which they can survive, grow, and divide.

FBS varies in composition according to where and when it was collected; usually causes unnecessary suffering for calves during collection; and is often contaminated with viruses. As a result, many researchers are seeking to develop serum-free alternatives as a matter of good cell culture practice.

Fetal bovine serum is a by-product of the Dairy Industry. Fetal bovine serum, as with the vast majority of animal serum used in cell culture, is produced from blood collected at commercial slaughterhouses from dairy cattle that also supply meat intended for human consumption.

The first stage of the production process for fetal bovine serum is the harvesting of blood from the bovine fetus after the fetus is removed from the slaughtered cow. The blood is collected aseptically into a sterile container or blood bag and then allowed to clot. The normal method of collection is cardiac puncture, wherein a needle is inserted into the heart. This minimizes "the danger of serum contamination with micro-organisms from the fetus itself, and the environment". It is then centrifuged to remove the fibrin clot and the remaining blood cells from the clear yellow (straw) colored serum. The serum is frozen prior to further processing that is necessary to make it suitable for cell culture.

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