It turns out these ideas aren’t quite right. The Dairy Alliance, a group that shares information about dairy products, explains that this indent, sometimes called a mold, is much more than just a decoration. It actually helps make the container strong enough to hold the milk. It also plays a role in making sure the correct amount of milk goes into the jug.
And to clear things up, the indent has absolutely nothing to do with spoiled milk. The Dairy Alliance confirmed that “the indent wouldn’t pop out because the milk’s age is just a little too old, even though such an invention would be helpful in a world of confusing dates on food packaging.” So, you can’t rely on the indent to tell you if your milk is past its prime.
Protecting Your Milk from Temperature Changes
This circular indent also helps protect your milk when temperatures change. According to Food Republic, a website known for recipes and cooking tips, these indents are made a bit larger in the summer. Why? Because plastic can shrink when it gets hot, and making the indent a little bigger helps prevent the milk from overflowing. In colder months, the indents are smaller, but rest assured, you’re still getting the same amount of milk all year round.
