Modified Fungal Agar Base is formulated as described by Mead and ONeill (1) for estimating moulds in cosmetics and toiletries. Earlier culture media developed for determining mould counts in cosmetics and toiletries etc. required upto 7 days of incubation for the valid count (2, 3, 4), unlike Mead and ONeill formulation which requires 3 days at 27.5 ± 0.5°C.
The medium contains casein enzymic hydrolysate, peptic digest of animal tissue, yeast extract, dextrose and inorganic salts which makes it a very nutritious medium. Potential contaminants of cosmetics and toiletries like Pseudomonas aeruginosa and Serratia marcescens are effectively inhibited by the Chloramphenicol in the medium. Sodium and potassium phosphates make the medium well buffered. Polysorbate 80 serves as a neutralizer of preservatives such as methyl paraben and physically hold or seclude the surfactants like sodium lauryl sulphate and lauroyldiethanolamide. These surfactants might suppress the growth or the spore germination of moulds (4). The pH of the medium is neutral which inactivates preservatives such as benzoic acid that is active at pH values below 6.0 but not active at pH near to the neutrality (3).
Storage and Shelf-life:
Store dry powder and prepared medium at 2-8°C. Use before expiry period on the label.
References:
1. Mead and ONeill, 1986, J. Soc. Cosmet. Chem., 37 : 49.
2. U.S. Food and Drug Administration, 1984, Bacteriological Analytical Manual, 6th ed., AOAC. Arlington, Va.
3. Williams (Ed.), 1984, Official Methods of Analysis of the AOAC, 14th ed., AOAC, Arlington, Va.
4. The United States Pharmacopeia, 1985, 21st rev., United States Pharmacopeial Convention, Rockville, MD.