MY 40 AGAR (OSMOPHILIC AGAR)

Description

Osmophilic yeasts usually are the cause of spoilage of high-sugar foods, including jams, honey, concentrated fruit juices, chocolate candy with soft centres etc. Osmophilic yeasts are of no public health significance, but are of economic importance to the food industry. A simple presence-absence test for detection of small numbers of osmotolerant yeasts in high-sugar foods is useful for enumeration. Osmophilic Agar (MY 40 Agar) is generally used for this purpose. Walker and Ayers in their review have differentiated between osmophilic yeasts and osmoduric yeasts. Almost all of the known osmophilic yeasts are Saccharomyces species e.g. Saccharomyces rouxii, var. polymorphus, Saccharomyces mellis etc. Improved recovery of osmophillic yeasts has been reported on media, which resemble the composition of the food under examination or contain high sugar concentrations. Osmophilic Agar is recommended for cultivation of a wide variety of osmophilic organisms. MY in MY-40 Agar stands for malt extract and yeast extract and 40 for the 40% of sucrose in the medium, which meets the requirements of the medium.