Exercise 7: Viable Count Procedure

Viable Count Procedue utilizes which plate method?

spread plate

VPC is quantitative or non-quantitative?

quantitative

for VPC, colonies grow and can be counted to determine:

original concentration of the starting sample

Viable cells means:

those that replicate and form colonies

Does the VPC method detect dead cells?

no

What is the dilution factor formula?

A/(A+B)

A=

volume being transferred

B=

volume being added to

Total Tube Dilution=

the total dilution of the original sample in each of the tubes

How do you calculate the total tube dilution?

multiple the combined dilution of the previous tube by the dilution factor of your transfer

Plate Dilution=

Amount Plated (in mL)/1 mL

A countable range is considered to be how many colonies?

anywhere from 30-300 colonies; CANNOT be any less or any more

How do you calculate the CFU/mL of a standard plate count?

calculate the dilution factors (DF) between the counted plate and the original culture; multiply the plate count by the reciprocal/inverse of the dilution factors

Results of plate count are reported as:

CFU/mL