"Secret" Ingredient in Potato Dextrose Agar (PDA)? - (Jan/14/2015 )

Hello,

I've heard a few rumors from companies that there is more to PDA than just potato infusion, dextrose (glucose), and agar.  When we prepare it in our lab and compare to supplier bought PDA, performance of our lab-made medium is less.  Has anyone heard of this rumor, or possibly has suggestions on how you make your PDA?

We currently make it using:

Glucose: 20g

Potato infusion powder: 4 g

Agar: 15g

Thanks in advance for any advice!

No secret. They use potatoes from the best of family farms in Idaho!

Joking aside, that's why people buy stuff from companies. The process standardization, consistency, etc.

The secret ingredient may be perfect pH too. When did you last calibrate your meter? :)