Yogurt production relies on the metabolic processes of specific bacteria, primarily Lactobacillus bulgaricus and Streptococcus thermophilus. These microorganisms consume the lactose (milk sugar) present in milk and convert it into lactic acid through a process called fermentation. This lactic acid lowers the pH of the milk, causing the milk proteins to coagulate, resulting in the thick, textured consistency characteristic of yogurt. This fermentation process is a form of anaerobic respiration, where the bacteria derive energy from lactose without the presence of oxygen.
This bacterial action offers several benefits. The lactic acid produced not only creates the desired texture but also acts as a preservative, extending the shelf life of milk. Furthermore, the metabolic activity of these bacteria contributes to the unique flavor profile of yogurt. Historically, yogurt production arose as a method of preserving milk in regions where refrigeration was unavailable, and its health benefits and palatability have led to its continued consumption across cultures.
