Starter cultures are specific strains of microorganisms, such as bacteria or yeast, used in the fermentation process of various foods and beverages. They help initiate fermentation by converting sugars into acids, gases, or alcohol, which enhances flavor, texture, and preservation. Common examples include Lactobacillus for yogurt and Saccharomyces cerevisiae for bread. These cultures are essential in producing a wide range of products, including cheese, sauerkraut, and beer. By introducing these beneficial microbes, starter cultures ensure consistent results and improve the safety and quality of fermented foods. They play a crucial role in traditional and modern food production methods.