It should be 172 billion, not million; I was multitasking. At 55 years old, memory is not as reliable has it has been, but I'm not willing to take that lying down.
I have been fiddling around with cell counting and viability for a couple of months now. Two weeks ago I took a weekend course at UWSP; microbiology for brewers. Their was only two homebrewers and about 12 local craftbrewers. It was a great weekend. The professor has been homebrewing for almost 20 years. We did some cell counting and viability. But, the professor's hobby is collecting bacteria and identification, so 95 percent of class time was spent on brewery bugs and there eradication.
I would be interested in exchanging ideas and procedures to improve the reliability and accuracy. I do need to state that I have only been doing this for the past few months.
My brewing process is tight, my fermentation temp control is +/- 1 degree ( liquid, not air contact), so accurate pitch rates are what I'm chasing now.