The culture I use is the proper salami culture, but my salamis don't grow any mold at all. An odd stick would have one or two pea size spots of ordinary gray mold but nothing like that nice white powder like substance.
Do I need to ask for a specific culture? Do you remember the name?
By the way, why do some salamis dry up and shrink and remain solid, while others retain about the same size but produce cavities inside? That seems to happen even within the same batch and I am sure even within the same load of a stuffer, though I am not 100% sure of the later.