Columbia Agar is used with or without blood for the isolation and cultivation of a wide variety of fastidious microorganisms. Conforms to Harmonized USP/EP/JP Requirements. Columbia Agar is not intended for use in the diagnosis of disease or other conditions in humans. A medium recommended by the Harmonized USP/EP/JP for isolation and identification of Clostridia from non-sterile products. Conforms to Harmonized USP/EP/JP performance specification. Originally described as a general purpose nutritious agar base by Ellner et al. at Columbia University that can be enriched by the addition of sterile blood. The peptone mixture and yeast extract provide a source of nitrogen, essential vitamins and amino acids. The starch provides a carbon source and sodium chloride maintains osmotic balance. The Harmonized European Pharmacopoeia states that where necessary, gentamicin sulfate at a concentration of 20mg/L can be added after sterilization to reduce the growth of non-target organisms. According to the Harmonized European Pharmacopoeia, Reinforced Medium for Clostridia is used as a selective enrichment broth, with subculture performed onto Columbia Agar.