I don't know. I think certain cultured foods are distinctive enough--it's hard to mistake a lacto-fermentation for an alcoholic one for instance--that maybe there are strong clues, especially if somebody's experienced enough, that things have gone right.

When it comes to gut bacteria and precisely what to do about them, I'm a bit skeptical about some people like Dr. Perlmutter and Dr. Davis whom I think are doing a lot of people a lot of good, and whether they really know what I should do about my gut bacteria. If something was obviously wrong with my doo-doo, I might change things up, but I think there are still clearer lights to steer by, how I feel, blood glucose, energy levels reductions in aches and pains (way less of these about a week and a half from fifty than I had when I was 30), better blood pressure now than then, etc.