Lots of the yeast and bacteria used in food manufacture were originally human skin flora. Which makes sense, since humans would be around to infect the first prototypes of these products. The first yogurt happened when somebody accidently stuck his thumb in the milk and then forgetfully let it sit out for a few days. He was probably pretty hungry or he wouldn't have tried to eat the stuff.
Many other products used wild yeast. The first alcoholic beverages were innoculated with airborne yeast spores. If you kept making the same beverage in the same place you'd tend to get the same yeasts. Eventually people figured out that the cloudy junk at the bottom of the wine or beer could be purposefully added to the malt/mash in order to get better quality control. I've made hard apple cider using wild yeast. In fact, if you use an old fashioned cider press it is almost impossible to prevent fermentation unless you pastuerize the juice.
But yeast cultures can give you more control over the product. Some yeast strains are more hardy and can withstand more alcohol before they die. If you use those you get a more potent beverage. Or maybe you want a sweeter beverage and use a different strain. If you use wild yeast you never know what you are going to get except through trial and error.
Bread yeast is the same. Wild yeasts would live in bakeries and the dough would get innoculated without anyone knowing why. Then someone figured out that they could save some old dough and purposefully innoculate the new dough. If you do this you can get much faster yeast growth, you can control the exact strain of yeast you use, and have more control over the bread you make.
Nowadays they grow yeast in big industrial vats then dry it out so it forms spores and sell it to consumers or food manufacturers. The only new step is intentionally drying and ensporulating the yeast so it can be stored longer.
Sunshine wrote:kyliealysha wrote:Yep. mangoes, fish, prawns, octopus *shudder*
That's not gross stuff though. I didn't count things like that - things that I don't like as I know lots of other people like them. My kids like avocado and they also like prawns - things I despise!