History of the San Andreas Fault, Gaspar de Portola, Andrew Lawson, Alfred Wegener and Harry Hess. The San Andreas fault is about 28 million years old. Back then, California didn't exist, at least not recognizably so. Bits and pieces could be found scattered around the western edge of North American, which at the time ended at the Pacific ocean lapping the shores of central Utah and Arizona.
Sourdough bread is made by the fermentation of dough using naturally-occurring lactobacilli and yeast. Sourdough bread has a mildly sour taste not present in most breads made with baker's yeast, due to the lactic acid produced by the lactobacilli.ourdough is a dough containing a Lactobacillus culture in symbiotic combination with yeasts. It is one of the principal means of biological leavening in bread baking, the others using cultivated forms of yeast.
Most commonly used microorganisms are yeast, bacteria, moulds, or a combination of these. A good example of microorganism usage in food production is the process of fermentation, which results in the production of organic acids, alcohols and esters. These help to either: 1  Preserve the food.athogenic microorganisms cause food-borne infections or intoxication, and include bacteria, viruses, parasites and moulds. It is important to note that pathogenic bacteria and viruses usually do not cause food spoilage, their contamination cannot be seen nor tasted.