Correct Response: D. Fermentation is a process that living organisms use to convert sugar to acids, gases, or alcohol. Many foods such as bread, yogurt, and alcoholic beverages are produced through the use of fermentation carried out by yeasts and bacteria. Emulsification (A) is the introduction of an ingredient (an emulsifier) for the purpose of preventing separation. This is typically used when a product includes oil and water. Emulsifiers can be natural ingredients, such egg yolks, but the process does not involve the use of living organisms. Homogenization (B) is also a way of preventing products from separating over time. The most common application is homogenized milk. Instead of adding an emulsifier, milk processors break up the large fat globules found in natural milk into much smaller globules that will not separate out over time. No living organisms are involved. Pasteurization (C) is a method of destroying pathogens in beverages and foods through the use of heat. It does not involve the use of living organisms.
