What was the source of the bacteria and yeast originally used in a dairy product fermentations and breads?

Probably similar to the source of the yeast used in wine fermentation.





I attended a seminar several years ago, presented by a researcher in the department here. He was studying origins and phylogenies (how the different kinds are related, kind of like a family tree) of wine yeasts. This is kinda gross - but wine yeasts were long thought to have been introduced on the feet of the people making the wine, you know, like the old Lucy show with them stomping around in a vat of grapes? Well, turns out it's more likely that the yeast drifted down from the birds nesting overhead.





But more generally, these yeasts were probably environmental, accidental introductions to dairy product that happily made cheese, or to flour, sugar, and water mixtures, happily making bread. There's a reason Jewish people aren't supposed to eat anything made with flour that's been wet for more th an something like fifteen minutes during Passover - that's how long it takes for fermentation to start, whether you add yeast or not, apparently. Eventually, people isolated and cultured the critters responsible (bacteria and/or yeast), and maintained them, sometimes guarding their particular formulas jealously.





Think about how to make Sourdough from scratch - you mix milk and flour and let it sit undisurbed until it bubbles. Generally. This even works if you use pasteurized milk (my grandmother had better luck making it with pasteurized milk on the Air Force Base in France than unpasteurized milk from the local dairy, or so the family tale goes)

What was the source of the bacteria and yeast originally used in a dairy product fermentations and breads?
The useful bacteria is often grouped under the term microflora and the productive ones are kept as a ongoing culture farm.





Read up on the link from Science Creative Quarterly.