Use of a Tobacco Agar Medium (TAM) to Detect Cryptococcus and Candida Colonies Isolated from Tobacco

Abstract The use of a tobacco agar medium (TAM) was investigated to visually differentiate Cryptococcus species from Rhodotorula and Candida species that can be isolated from tobacco. This study was first conducted with pure isolates of each of the major yeast species that have been isolated from tobacco. All Cryptococcus strains that were tested produced colonies with different degrees of pigmentation ranging from light to dark brown or black. All Candida and Pichia colonies were white to off-white. Candidaparapsilosis colonies were easily differentiated since they had rough contours and surfaces. All Rhodotorula colonies were pink or orange. In order to validate the use of this medium, tobacco was spiked with a mixed culture of Cryptococcus, Candida, Rhodotorula and Pichia. TAM allowed visual detection and enumeration of the four yeast genera based on colony colour and/or morphology.