Dichloran-Glycerol (DG-18) Agar

Dichloran-Glycerol (DG-18) Agar is recommended for the enumeration of yeast and molds that develop in products with low water activity (aw less than 0.95). The media finds particular applications for the enumeration and isolation of xerophilic molds which may be found in dehydrated or extremely dry products, such as heavily sugared or salted foods, dried fruits, cereals, cakes and cookies, flour and meat or fish based dehydrated products. The media favors a controlled growth regarding the size and breadth of mold mycelia and yeast colonies, allowing easier and more accurate counts.

The typical composition of the media corresponds to that defined in the standards NF V08-036 & NF ISO 21527-2

Principles

• Tryptone and glucose assure the growth of yeasts and molds
• Concentration of glycerol at 18% results in a diminution of the water content from 0.999 to 0.955
• Dichloran inhibits the invasion of molds and reduces the size of other colonies
• Presence of Chloramphenicol,  heat resistant antibiotic, reinforces the selectivity of the medium against the majority of bacterial contaminants.