Fermentation is a traditional method of food preservation that enhances shelf life by converting sugars into acids, gases, or alcohol using microorganisms. This process creates an environment that inhibits the growth of spoilage-causing bacteria. It is widely used in preserving vegetables, dairy, cereals, and meats. Fermented foods like yogurt, kimchi, sauerkraut, and pickles are rich in beneficial probiotics. The process also improves the nutritional profile and digestibility of foods. Natural acids produced during fermentation lower the pH, making the food less hospitable to harmful microbes. This method requires minimal equipment and is sustainable. Overall, fermentation contributes to both food safety and flavor development.