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The Variety and Roles of Microbes

Author(s): Barbara Tharp, MS, and Nancy Moreno, PhD

Examples of Microbes in Food Production/Processing

One of the most common uses of microbes in food preparation is the process of fermentation. Although oxygen usually is necessary to transform the energy in food, some species of bacteria and fungi are able to complete this transformation in an oxygen-free environment. In the absence of oxygen, these microbes break down food, often sugar and other carbohydrates, thereby creating by-products such as CO2, ethyl alcohol and lactic acid. This naturally-occurring process has been utilized by humans to prepare many kinds of food products.

In ethanol fermentation, for example, microbes release ethyl alcohol and CO2. This process is used to produce many alcoholic beverages, including wine (from fermented grapes), as well as foods like bread (in which the alcohol is baked off, and CO2 causes the bread dough to rise during baking). The fermentation of rice results in saki. Vodka is made from fermentation of grains or potatoes.

The other most common type of fermentation used in food production is lactic acid fermentation, which gives foods like yogurt and pepperoni their slightly sour flavor.

Funded by the following grant(s)

Science Education Partnership Award, NIH

Science Education Partnership Award, NIH

Grant Number: 5R25RR018605