In the modern food technology era, one of the aims of food safety and quality is to eliminate or reduce the number of microorganisms in food. This may now be changing. In particular, the importance of live microorganisms as beneficial food constituents is now being recognized. Microorganisms present in food that contribute to the human diet include not only viable bacteria but also metabolites and bioactive components. Yogurt is one of the most biologically active foods consumed by humans. It is an excellent source of proteins, vitamins, and minerals. Additionally, the nutritional value is especially high relative to cost. Potential nutritional benefits are also associated with the ingestion of the bacteria that are ordinarily present at the time of consumption. Thus, yogurt serves as a major source of live bacteria in the human diet, as well as a delivery vehicle for added probiotic bacteria. Yogurt may provide a simple and affordable solution for enhancing the nutritional value of the diet, including the intake of live bacteria and their metabolites. A further benefit may be obtained when yogurt is used as a carrier for specific probiotic bacteria and/or prebiotic compounds. These factors suggest that yogurt could have a more visible role in food-based dietary guidelines.