Why do the enteric plates sometimes look like they are contaminated with fungus?
A. During prolonged storage, SS and HE plates will occasionally exhibit “spider” or “snowflake” like formations in the media. These formations are caused by bile precipitates. Although it may look like fungal contamination, it is not. Both of these media contain a high concentration of bile which is used to inhibit gram-positive bacteria. Although a cosmetic defect, it does not influence the growth characteristics of the media.
