Re: How can I identify penicillium?

It is quite possible that the bluish mold is Penicillium.  Penicillium 
species are common food contaminants, found growing on cheeses.  A "text 
book" colony morphology of Penicillium is as follows: The surface might 
at first appear white then becoming very powdery, turning bluish-green 
with a white border.  

If you have access to a microscope and some staining solutions you could 
look at the cellular morphology of your suspected Penicillium isolate.  I 
have included a scanned diagram of the cellular morphology of 
Penicillium. Shown in the diagram is the spore formation that is 
indicative of Penicillium species.  The spores known as conidia are held 
to hyphae by structures known as the sterigmata and metula.  The picture 
is taken from "Medically Important Fungi: A guide to Identification" by 
Davise Honig Larone.