A modified creatine sucrose medium for differentiation of species in Penicillium subgenus Penicillium.

The creatine sucrose agar originally described by Frisvad was modified by varying the sucrose and creatine concentrations and pH over a wide range. After extensive tests with commonly occurring species in Penicillium subgenus Penicillium, a new formulation was derived, which is termed neutral creatine sucrose agar. This medium produced eight different reactions among the 20 species tested, and hence has the potential to be a very useful taxonomic medium for species in this difficult subgenus.