Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.

Part 1: pH scale:

• A pH scale is used to measure whether the substance is an acid or a base.
• The pH scale ranges from 0 to 14.
• The pH value of the acidic solution is less than 7, the neutral solution is equal to 7 and the basic solution is greater than 7.

Part 2: pH changes when milk changes to curd;

• Milk can be converted into curd through the process of fermentation.
• When the milk is converted into curd by the action of bacteria, the lactic acid is formed and it is more acidic in nature.
• Thus the pH value of the milk will get reduced from 6 when it turns to curd.

Therefore, when milk turns to curd, the pH value of the milk gets reduced.