Description
Amyl mem Faecal Coliform Broth, AM 113, and mem Faecal Coliform Agar, AM 124, are compounded according to the formulation described by Geldreich et al, who reported use of the media as part of an elevated temperature, membrane filtration procedure for the isolation of faecal coliforms from polluted waters1.
The nutritional elements of the media include peptones as a source of nitrogen and lactose as a major carbohydrate source for the lactose fermenting coliforms. Yeast extract supplies vitamins and other growth factors, while osmotic equilibrium is maintained by the presence of an appropriate level of sodium chloride. Bile salts act as a selective agent for the inhibition of gram positive organisms. The optional addition of Rosolic Acid bestows a differential characteristic upon the media, enabling easier recognition of the blue colonies of lactose fermenting coliforms in contrast to the cream to grey coloured colonies of other organisms. The media assume a cherry red colour when Rosolic Acid is incorporated.
