For detection of Salmonella spp. LYSINE DECARBOXYLASE MEDIUM (as per ISO) used for the biochemical confirmation of Salmonella species. Lysine Decarboxylase Medium was originally developed by Falkow. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate. Bromocresol purple is the pH indicator. Lysine monohydrate is added to detect the production of the specific enzyme. When the medium is inoculated dextrose is fermented, the acid produced lowers the pH of the medium and changes the color of the indicator from purple to yellow. The bacteria that decarboxylate the Lysine monohydrate is decarboxylated to cadaverine, such as Salmonella, are identified by the prescence of a purple- red colour due to elevation of the pH. A yellow colour after 24 hours indicates a negative result. The tubes are inoculated with the microorganism samples and incubated for 24 ± 3 hours at 37 ± 1°C.