Some psychrophiles, can create a spoilage problem in meat coolers and other refrigerated storage areas.īecause yeasts can grow under conditions of high salt or sugar content, they can cause the spoilage of certain foods in which bacteria would not grow. In fact, the fermentation of wine and beer is often carried out at temperatures near 4☌ (40☏). Some yeasts are psychrophilic, meaning they can grow at relatively low temperatures. During this fermentation process, little bubbles of carbon dioxide released from the yeast fill the dough and cause it to expand or “rise.” A slice of bread can be examined with the naked eye or with a magnifying glass to see the many small spaces made by the carbon dioxide. The yeast used in bread production consumes the sugars present in bread dough, using the energy for growth and reproduction and releasing carbon dioxide and alcohol. Although this is the most common method of reproduction, yeasts also multiply by the formation of spores. A small knob or bud forms on the parent cell, grows and finally separates to become a new yeast cell. Yeasts reproduce by a method called budding. From these they produce carbon dioxide and alcohol. Most types of yeast can live only on sugars and starches. They also play the initial role in the production of vinegar.
They are responsible for the rising of bread dough and the fermentation of wine, whiskey, brandy, and beer. Yeasts have been useful to humans for centuries in the production of certain foods and beverages. They are members of the kingdom Fungi (singular, fungus), that also includes mushrooms and differs from plants in that these organisms have no chlorophyll.
Yeasts are small, single-celled organisms.
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