CULTURAL ASPECT AND QUALITY CONTROL
Salmonella typhimurium ATCC 14028: good growth; red (same colour as the
medium / translucent) colonies with black center;
Escherichia coli ATCC 25922: inhibited yellow colonies;
Shigella flexneri ATCC 112022: colorless colonies;
Enterobacter cloacae ATCC 13047: yellow colonies.
Enterococcus faecalis ATCC 29212: no growth.
Yeast extract 3.0 g, L-Lysine HCl 5.0 g, xylose 3.75 g, lactose 7.5 g, sucrose 7.5 g,
sodium desoxycholate 1.0 g, sodium chloride 5.0 g, sodium thiosulphate 6.8 g, ferric
ammonium citrate 0.8 g, phenol red 0.08 g, agar 13.5 g.
Distilled water ad 1000ml; adjust pH to 7.4 ± 0.2. Do not overheat.
Medium used for isolation and identification of Salmonella and Shigella. H2S-positive organisms form black colonies. Fermentation
of xylose, lactose and sucrose results in yellow colonies, sometimes together with medium yellowing around colonies. Lysine
decarboxylation produces a purple colouration around the colonies.
Composition formula is included in SR EN ISO 6579 standard "Horizontal method for the detection of Salmonella spp.".
(Xylose, Lysine Deoxycholate agar)
(c) Costin Stoica