What is a natural source of lactic acid?

Lactic acid is a natural organic acid that is produced in various foods, particularly during the fermentation process. Sour milk is a prime example as it contains lactic acid formed from the fermentation of lactose by lactic acid bacteria. This process not only contributes to the sour flavor of the milk but also enhances its preservative qualities and nutritional value.

In the case of sour milk, the presence of Lactic Acid bacteria leads to the production of lactic acid, making it a rich source. This is a common occurrence in products like yogurt and kefir where bacterial fermentation of milk occurs.

The other selections do not have significant natural concentrations of lactic acid. While honey, wheat, and lemons have their own beneficial nutrients and acids, they do not undergo the same fermentation processes to produce lactic acid like sour milk does. Overall, sour milk stands out as the most direct and notable natural source of lactic acid.