I'm only a little bit into "The Art of Fermentation," but I think the applicable catchphrase wanted here is "selective environment." Mr. Katz' books go a long way toward debunking the presumed necessity of "science" to ensure "safety." We would never have learned to fear botulinum toxin, he explains, if we hadn't tried to improve on fermentation by sterilizing our food, i.e., canning.
I took a little molecular biology in school. As I recall (with difficulty) it was mostly about how pH and salinity determine whether this or that protein takes a form that allows it to polymerize or otherwise function. I think that chemistry basically scales up to this effect, because the substances are those that alter protein structure: salt, alcohol, acid.
Reading abstracts in medicine (dermatology is a special interest) and nutrition more lately has led me to speculate that what makes a tonic effective in improving the integrity of our own organism is the diversity of carboxylic acids our bacterial allies give us. Molecules of various sizes to penetrate all our organs and tissues and clear calcium from its protein binding sites, making the processes of life flow like a water heater that has been unburdened of its hard water encrustations.
Finally, the microorganisms living in us benefit from the selective environments provided by our optimally functioning bodies. The "acid mantle" of our skin is most familiar and accessible to direct manipulation. Tonic beverages are to our guts what acid toners (chemical exfoliators) are to our skin. I couldn't figure out previously why people referred to pumpkin enzyme, when no protein is ever specified. That's actually an old presumption from the history of fermentation, that the enzymes decomposing a vegetable are the functional constituent. The cosmeceutical makers simply ferment pumpkin juice and call it "enzymes."https://www.bulkactives.com/product/pro ... rment.html
PAY NO ATTENTION TO THE PICKLE MAN BEHIND THE CURTAIN!