One of the natural sources of lactic acid is:

Correct option is D

Lactic acid is naturally produced during the fermentation of milk by lactic acid bacteria. This process converts lactose (milk sugar) into lactic acid, giving curd its sour taste. Thus, curd is a natural source of lactic acid.

Information Booster

• Curd: Contains lactic acid due to the activity of lactic acid bacteria (e.g., Lactobacillus species).
• Other sources of lactic acid: Naturally occurring in fermented products like sour milk, yogurt, kimchi, and pickles.
• Lactic acid plays a vital role in preserving food and contributes to the tangy taste of fermented products.
• Orange contains citric acid, which is responsible for its tangy and sour taste.
• Vinegar contains acetic acid, which gives vinegar its distinctive sour taste and pungent smell.
• Tomato contains oxalic acid and small amounts of citric acid.​