Hi 
 
Thank you
Let me give you an example
 
We do a powdered blend that only contains 3 ingredients which are very low risk.
 
A client has asked for the microbial limits for that blend
 
I have tried searching for that blend on the net to get a microbial limits and failed, hence was looking for maybe each ingredient microbial limit and come to a limit for the specification for our product.
 
Hope  this makes sense
 
yes i understand.   You will probably not find a manual or book of some king with that info.  
 
my suggestion to you would be 
 
1.   test the product multiple times to establish the highest possible levels.   then add a little bit for some wiggle room. 
2.  use the specifications from the raw materials.    pick the ingredient with the highest limit and use it.   
3.   Your suppliers may have a ridcuously high spec limit.   for this reason a combination of #1 and #2 might make sense.