I am a skeptic when it comes to magic elixirs containing microbes.
My thinking is that it is virtually impossible to bring any species of microbes to extinction when starting with populations of 10E+10 to the teaspoon. Surely even a few of each species will survive no matter how austere and uninviting the circumstances are for that particular species. And then, those few microbes per teaspoon are enough to restart the population when conditions for that species improve.
The young lady made a compelling case to the contrary.
Her arguments centered on communities or guilds of microbes. She talked about energy and nutrient pathways. She touched on how yeast change the pH of wort when beer is brewed and how the lowered pH and growing ethanol percentage favors the good yeasts.
She talked about critical masses of populations and how onesie-twosie are not enough to mold the environment to make it favorable for that environment.
She gave testimony centered on her parents beekeeping enterprise. The bees were stressed and came down with dysentery. A professor at University of Wisconsin whipped up a brew of good-bee-bacteria. The day was saved. She was inspired to market the good-bee-bacteria because she knew other beekeepers are plagued by bee dysentery.
She cautioned: Don't feed your bees yogurt, buttermilk or kefir. Those are great bacteria for human guts but are not good for bees.
I don't know that I am entirely convinced because I hate spending money...but she made some pretty good points.