Which processing method involves the use of microorganisms?

Fermentation is a processing method that utilizes microorganisms, such as bacteria, yeast, and molds, to transform raw ingredients into food products through biochemical processes. During fermentation, these microorganisms feed on sugars and produce by-products like alcohol, carbon dioxide, and various acids, which can enhance flavor, texture, and preservation of the food. Common examples of fermented foods include yogurt, sauerkraut, beer, and sourdough bread. The role of microorganisms in fermentation not only contributes to the unique characteristics of these foods but also can improve their nutritional value and shelf life.

In contrast, canning, freezing, and dehydration are methods that involve physical changes to food to preserve it, but they do not employ microorganisms in the same way. Canning uses heat to kill microorganisms and create a vacuum seal, freezing halts microbial activity by lowering temperatures, and dehydration removes moisture to inhibit microbial growth. None of these methods harness the beneficial transformations brought about by microorganisms, which is the essence of fermentation.