What type of bacteria is often deliberately introduced in yogurt production?

In yogurt production, lactic acid bacteria are deliberately introduced because they play a crucial role in the fermentation process. These bacteria, primarily strains like Lactobacillus bulgaricus and Streptococcus thermophilus, convert lactose (the sugar found in milk) into lactic acid. This process not only helps to thicken the milk into yogurt but also lowers the pH, creating an environment that is less favorable for harmful bacteria to thrive. Additionally, the production of lactic acid contributes to the tangy flavor and creamy texture that yogurt is known for.

In contrast, pathogenic bacteria are harmful and can cause foodborne illnesses, which is why they are not intentionally introduced in food production. Coliform bacteria are used as indicators of sanitation and potential contamination in food products, but they are not specifically desirable in yogurt. Cheese-making bacteria, while effective for curd formation in cheese production, do not have the same beneficial properties for yogurt fermentation as lactic acid bacteria do. Therefore, the presence and activity of lactic acid bacteria are essential for the successful creation of yogurt.