For selective isolation and enumeration of yeasts and molds from environmental materials and foods. Rose-Bengal Chloramphenicol Agar is a selective medium for the enumeration of yeasts and moulds from environmental materials and foods. Rose Bengal Chloramphenicol Agar was formulated originally by Jarvis and further modified by Overcast and Weakley. The use of Rose Bengal in the media having neutral pH was reported by Smith and Dawson. Several investigations have found a neutral pH with the addition of a selective agent have been successful in supporting fungal growth and restricting bacterial growth. This medium is recommended in standard methods for the enumeration of yeast and molds from foods and water.
Mycological peptone provides nitrogen and vitamin sources required for organism growth in Rose Bengal Chloramphenicol Agar. The high concentration of Dextrose is included as an energy source. Monopotassium Phosphate is a buffering agent. Magnesium Sulfate provides trace elements. Rose Bengal is included as a selective agent to inhibit bacterial growth and restricts the growth of rapidly growing molds. Rose-Bengal is taken up by mould and yeast colonies thereby assisting enumeration of small colonies. Rose-Bengal also controls the size and height of mould colonies, such as Neurospora and Rhizopus spp. Over-growth of slow growing strains by more luxuriant species is thus prevented and plate counting is assisted. Chloramphenicol is a broad-spectrum antibiotic inhibitory to a wide range of Gram-negative and Gram-positive bacteria. Agar, Bacteriological is the solidifying agent.