LYSINE IRON AGAR (VEG.)

This medium is prepared by replacing Peptic digest of animal tissue with Veg peptone which makes the medium free of BSE/TSE risks. Lysine Iron Veg Agar (Veg) is modification of Lysine Iron Agar which was developed by Edwards and Fife to detect lactose fermenting Salmonellae. Salmonellae are known to decarboxylate lysine rapidly and produce large amounts of hydrogen sulphide. This medium is a sensitive medium for the detection of lactose fermenting and lactose non-fermenting Salmonella species. Many strains of this group ferment lactose very rapidly thus suppressing hydrogen sulphide (H2S) production on Triple Sugar Iron Agar (Veg). So there is a possibility that the organisms frequently found in food poisoning outbreaks could be overlooked. Thatcher and Clark described the isolation of Salmonella species from foods from selective agar and to inoculate it on Lysine Iron Agar (Veg) and Triple Sugar Iron Agar (Veg) together. Using these two media greater discrimination can be made between coliform organisms e.g. Escherichia and Shigella.

for di?erentiation of enteric organisms especially Salmonella species based on their ability to decarboxylate or deaminate lysine and production of H2S