Colony count

Stephen Mamber mamber at
Mon Jan 22 10:14:36 EST 1996

In article <4dhp2k$4lf at>, scooter at (jane venghaus) says:
>We count 30-300 colonies on a 100mm plate and say that number is 
>significant.  But what is the equally significant range for colony
>counts of coliforms on a 60mm plate?  

A range of 30-300 CFU/plate is always good, no matter what the size - 
for example, counts on 47 mm membrane filters.  I suppose, however,
that you can go to, say, 20-200 CFU/plate if pressed.  Have you checked 
with Standard Methods for the Examination of Water & Wastewater lately?  


mamber at

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