Antifoam function as an effective foam suppressor. Antifoam 204 contains 100% active components and is a mixture of organic non-silicone polypropylene-based polyether dispersions. It does not contain mineral oil. Antifoam 204 can itself be considered a surfactant, but it contains no other surfactants. This product is synthetic and not derived from animal or plant sources. Antifoam 204 can be sterilized repeatedly. The flow properties of Antifoam 204 are such that it can be pumped to a fermenter on an as-needed basis. For use in microbiological media, Sigma recommends a starting concentration of between 0.005% and 0.01%.