NEET BIOLOGY

Detailed explanation-1: -Lactic acid bacteria convert the sugars in milk (lactose) into lactic acid, with carbon dioxide as a by-product. The milk is heated to a mild temperature (around 25°C) to allow the bacteria to grow and divide. An enzyme called rennet is added that makes the fermented milk coagulate and stick together.

Detailed explanation-2: -Yogurt is a popular fermented dairy product produced by lactic acid bacteria, including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus.

Detailed explanation-3: -The function of the starter cultures is to ferment lactose (milk sugar) to produce lactic acid. The increase in lactic acid decreases pH and causes the milk to clot, or form the soft gel that is characteristic of yogurt. The fermentation of lactose also produces the flavor compounds that are characteristic of yogurt.

Detailed explanation-4: -Both yogurt and cheese utilize starter cultures to produce acidity. However, in both, the exact type(s) of cultures can vary. Some cheeses use cultures such as Streptococcus thermophilus and Lactobacillus bulgaricus. Yogurt can also use cultures like Lactobacillus acidophilus and Bifidobacterium.