***PLEASE HELP-milk microbiology project

[Paul Party]

I am doing a project entitled:
'Investigating how different milk types (skimmed/whole and
UHT/Pasteurized) and days milk is left at room temperature unexposed,
affects the bacterial content'

I am measuring bacterial content by counting colonies on incubated milk
agar plates and also carrying out titrations against sodium hydroxide in
order to measure lactic acid content.

I would be very grateful if anyone could provide any relevant background
information about milk microbiology information and what results I should
expect from each of the different milk types and why.

Thanks very much.
S.Paul