I have been using Wallerstein Differential media for my aerobic/anaerobic baceterial count. Until now, I've always gone by the directions- counting dark green colonies as bacterial and any white/light green colonies as cyclohexamide resistant yeast. However, there have always been some ambiguities (colonies with a dark green center but otherwise white or filamentous colonies with dark green bacterial colonies on the inside).
My pH indicator showed my pH was dropping on my plates where there was only white colonies. I decided to pick some colonies and examine them under the microscope. What I had assumed was wild yeast is most definitely lactobacillus (rod shaped, catalase negative).
I did see some yeast in one of the very light colonies I picked but overall I am seeing lacto.
Does anyone have any experience with this. I am trying to collect some precise data and this is certainly holding me back.
For the record, I'm pour plating with 5 ml samples for aerobic plates, incubated for 3 days and 2.5 ml samples for anaerobic plates, incubated for 7 days. I'd definitely be open to switching to UBA if I thought it would help.
My pH indicator showed my pH was dropping on my plates where there was only white colonies. I decided to pick some colonies and examine them under the microscope. What I had assumed was wild yeast is most definitely lactobacillus (rod shaped, catalase negative).
I did see some yeast in one of the very light colonies I picked but overall I am seeing lacto.
Does anyone have any experience with this. I am trying to collect some precise data and this is certainly holding me back.
For the record, I'm pour plating with 5 ml samples for aerobic plates, incubated for 3 days and 2.5 ml samples for anaerobic plates, incubated for 7 days. I'd definitely be open to switching to UBA if I thought it would help.
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