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Bacillus Cereus (Mannitol Egg Yolk Polymixin - MYP) Agar Intended for the selective enumeration of Bacillus cereus in food samples the medium uses two reactions (Mannitol fermentation and Lecithinase production) to differentiate Bacillus cereus from other members of the species. As Bacillus cereus is Mannitol Negative the colonies are pink in colour due to the presence of Phenol Red Indicator. Lecithinase production (from the Egg Yolk) is indicated by a white precipitate around the colonies. Polymixin is added as the selective agent to inhibit coliforms. NB: It should be noted that some Proteus spp and gram positive cocci may grow on this medium. -
Bacillus cereus agar (PEMBA) is used for the selective isolation and enumeration of Bacillus cereus in food samples. It is said to be particularly suitable for the detection of small numbers of Bacillus cereus particularly in the presence of other contaminating organisms. Bacillus cereus agar (PEMBA) is based on the formulation developed by Holbrook and Anderson. The peptone provides the required carbon, nitrogen and vitamins. Mannitol is a fermentable carbohydrate. Bromothymol blue is a pH indicator used to detect mannitol fermentation. Sodium chloride maintains the osmotic balance. Magnesium sulphate provides divalent cations and sulphate. Di-sodium hydrogen phosphate and potassium dihydrogen phosphate are buffering agents. Egg yolk emulsion (BM0140) must be added to this media to assess lecithinase production. Sodium pyruvate is present to improve egg yolk precipitation and enhance B. cereus sporulation. The medium is made selective by the inclusion of polymyxin B sulphate (LS1051). -
Brilliant Green Agar This medium is intended for use in the isolation of Salmonellae other than Salmonella typhi. Although it can be used as a primary isolation medium it is not recommended for this purpose and is generally used for subculture from selective enrichment media. It should be noted that the medium is highly selective and therefore not suited to the isolation of Salmonella from samples where the numbers may be low. NB: It is not recommended that this medium be used for the isolation of Salmonella typhi and Shigella spp.
