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

The pH value of the milk will get reduced from 6 when it turns to curd.
Fermentation is the name for the process that turns milk into curd. The globular casein protein is present in milk. Casein and lactic acid bacteria react chemically to form curd. The pH of fresh milk will decrease from 6 because during curd formation, as lactic acid is produced which makes it acidic. 

Therefore, when milk changes into curd its pH changes and becomes less than 6.