how to do Aspergillus Niger count? - (Apr/04/2014 )

Hi, I'm facing problem in counting my Aspergillus Niger. 

I grew the Aspergillus Niger on Sabouraud dextrose agar with chloramphenicol(SDAC), incubated for 5 days. Then I washed the plate with 9ml of 0.001% Tween 80, this I considered as 10⁸ suspension.

Then I diluted to 10² suspension and took 0.1ml to do spread plate on SDAC, incubated for 5 days.

The problem is after 5 days incubation, my Aspergillus grows all over the agar surface, I cannot get separate colonies.

May I know what is the proper way to count the Aspergillus? I need to know the viable count for my 10² suspension.

Thank you.

Sounds like USP <51> based protocol.  If you're using ATCC 16404 - the correct species name is Aspergillus brasiliensis,  Folks typically count colonies earlier than 5 days - look every day.

I'm using ATCC 6275. I tried to count on the 3rd days, but I only got 4 colonies this time.

Any proper protocol on how to collect the spores and prepare exactly 10² suspension?

Thanks.

That's a matter of your consistent execution of protocol and appropriate dilution.  Looks like your assumption of 10E8 is not correct.