Interesting Milk Dehydration Product

Dried milk - N. Carlson

At the bottom of a glass of milk that spent too much time in a bedroom this spongy object formed. It looks like a sunny side up egg.  It appears to consist of dehydrated milk solids.

Bottom side of dried milk - N. Carlson

The underside is hollowed out. I attempted to grow portions of the material on culture plates, TSA, DG-18 and MEA. The plates were placed in a 25C incubator. There was minimal growth on the plates other than yeast.