What is the pH levels of expired milk sour cream and yogurt and Does it become more acidic as it gets more expired?

Expired milk, sour cream, and yogurt typically have lower pH levels than their fresh counterparts, often ranging from 4.0 to 5.5, indicating increased acidity. As these dairy products expire, lactic acid bacteria continue to ferment lactose, producing more lactic acid, which decreases the pH and makes the products more acidic. Therefore, as they become more expired, their acidity generally increases.