Hi there, I'm about to conduct an experiment where I look at the effect of sugar on the shelf life of yoghurt. I plan to measure this by quantifying the number of lactic acid bacteria in each sample by using bromocresol purple pH indicator.
However, before I do the experiment, I was wondering what kinds of problems I can expect using bromocresol purple indicator in the MRS agar in terms of errors and practicality so I can minimise these problems.
I plan to use 0.025ml per litre.
Also, I've never used this indicator before so what can I expect in terms of the colour the agar will be when I add it to the plates? Will it be initially all purple and after incubation, there will be some yellow colonies signifying lactic acid bacteria?
Really really appreciate the help!