Enumeration of Yeast and Mould Count (FDA BAM Chapter 18)

Hi, I am using FDA BAM Chapter 18 method for Enumeration of Yeast and Mould Count.

I plate 0.1ml of sample onto 3 agar plates.

Would like to ask on the results calculation. What if there is only 1 or 2 colonies grow from all these 3 plates? 2 divide 3 = 0.66

What number to take as the result?

Report as ND <100?

Thank you.

Hi, I am using FDA BAM Chapter 18 method for Enumeration of Yeast and Mould Count.

I plate 0.1ml of sample onto 3 agar plates.

Would like to ask on the results calculation. What if there is only 1 or 2 colonies grow from all these 3 plates? 2 divide 3 = 0.66

What number to take as the result?

Report as ND <100?

 

Thank you.

I assume sample is from 10(-1) dilution.

(it might have been advisable to also evaluate the 10(-2) dilution)

Note that BAM (Pour Plate method) suggests to use plates with 10 -150 colonies

By analogy to BAM's APC counting section I suggest a result <1000cfu/gram

APHA (2001) would suggest (assuming total 2 colonies) a result of 67cfu/gram (est.)

IIRC ISO have a third calculation method.

All very hypothetical.

A pour plate method using 1 ml inoculum might be helpful..