The quality and safety of fermented milk products, which make up a sizeable portion of human nutrition, are greatly influenced by both the milk itself and the starting cultures employed to ferment it. Lactic acid bacteria (LAB) create a variety of metabolites throughout the fermentation process, altering the organoleptic properties of the substrates. The final product's nutritional value and digestibility are enhanced by fermentation of the raw materials, which also adds vitamins, vital amino acids, and fatty acids. The quality and safety of fermented milk products, which make up a sizeable portion of human nutrition, are greatly influenced by both the milk itself and the starting cultures employed to ferment it. The inhibition of the growth of pathogenic microbes, which lowers the likelihood of the emergence of foodborne diseases, is another crucial function of LAB. A variety of pathogenic bacteria are frequently present in raw (unpasteurized) milk, and other raw materials; these pathogenic bacteria should be removed during the fermentation process. As a result, a variety of LAB metabolites, such as hydrogen peroxide, organic acids, and bacteriocins, function as bio preservative agents, enhancing food safety and lengthening the shelf life of the finished products.