Brilliant Green Agar (modified)

(Phenol Red Brilliant Green Agar, BPLS)

LAB 34

Description

First introduced by Kristensen et al in 1925 as a selective medium for the isolation of salmonellae (except S. typhi). The medium was modified by the Netherlands Institute for Public Health, Utrecht. The modification was to increase the selectivity of the medium by increasing the dye concentration. This formulation is quoted by the International Standards Organisation, standard European Community Methods, the American Public Health Association and the Association of Official Analytical Chemists. The medium is suitable for subcultures from selective enrichment media. However because this medium is highly selective, small numbers of salmonellae may be missed. This medium is definitely not recommended for S. typhi

and Shigella spp. Less inhibitory media such as X.L.D. and Hektoen Enteric Agar will be useful in detecting salmonellae and shigellae inhibited by Brilliant Green Agar.

Method for reconstitution

Weigh 52 grams of powder and disperse in 1 litre of deionised water. Allow to soak for ten minutes and then bring to the boil with frequent swirling to dissolve the solids and cool to 47˚C in a water bath. Pour plates and dry the surface before inoculation. DO NOT remelt or autoclave: overheating causes precipitation of the medium. Store plates away from light.

Appearance: Tan, clear gel.

pH: 6.9 ± 0.2

Minimum Q.C. organisms: Salmonella sp. NCIMB 50076 E. coli (inhibition) NCIMB 50034

Storage of Prepared Medium: Plates - up to 7 days at 2-8˚C in the dark.

Inoculation: Surface streaking for single colonies, a heavy inoculum can be used.

Incubation: 37˚C for 18-24 hours aerobically.

References

Edel, W. and Kamplemacher, E.H. (1968). Comparative studies on Salmonella isolation in eight European laboratories. Bull. Wld. Hlth. Org. 39: 487-491.

Edel, W. and Kamplemacher, E.H. (1969). Salmonella infections in nine European laboratories using a standard technique. Bull Wld. Hlth. Org. 41: 297-306.

American Public Health Association (1966). Recommended Methods for the Microbiological Examination of Foods, 2nd end. (ed. J.M. Sharf) A.P.H.A. Washington.

Association of Official Analytical Chemists (AOAC) (1978) Bacteriological Analytical Manual, 5th edn., Washington D.C.

Pharmacopoeia of culture media for food microbiology. (1987). Int. J. Food Microbiol. 513: 245-247. 3/112