MALT AGAR, W/ 2% AGAR

Description

Media based on malt extract may be considered as general growth substrates due to their richness and nutrient balance. They are very suitable for the cultivation of fastidious microorganisms. With acidic pH, they are used for the isolation, cultivation and maintenance of yeast and moulds. Malt media for yeasts and moulds have been widely used for many years. In 1919, Reddish prepared a satisfactory substitute for beer wort from malt extract. Malt Agar, w/ 2% Agar is recommended for the detection and isolation of yeasts and moulds from dairy products, foods and other materials. It is also recommended by FDA BAM for the study of yeast and moulds from cosmetics. This medium can also be used for maintaining stock cultures of fungi. For isolation of yeasts and fungi from cosmetics, preliminary sample preparation is done in accordance with the BAM protocol. Add either 5 or 10 ml of prepared cosmetic preparation depending on the type of the sample to 45 or 90 ml, respectively, of MLB, for 10-2 dilution. Dilute samples decimally in Letheen Broth, modified to obtain complete dilution series from 10-1 to 10-6. Total yeast and mould count is checked using spread plate technique. 0.1 ml portions of each dilution in duplicates is transfered to appropriately labeled plates of either Malt Agar, w/ 2% Agar or Potato Dextrose Agar w/2% Agar, both containing 40 ppm Chlortetracycline. Incubate up to 7 days at 30 ? 2?C and report the counts as the average of the two plates. For enrichment of fungal cultures, dilute prepared sample decimally in Sabouraud’s dextrose broth and incubate as described above. If growth occurs, sub culture on Sabouraud’s dextrose agar, Malt Agar, w/ 2% Agar or Potato Dextrose Agar w/2% Agar with 40 ppm chlortetracycline on later 2 agars.