Ever noticed the circular indent on plastic milk jugs? It’s not just for looks. While social media has sparked theories—from spoilage indicators to cold weather expansion—the real reason is far more practical.
According to The Dairy Alliance, the indent helps the jug stay sturdy, controls how much milk is filled, and reduces the risk of spills. Despite rumors, it doesn’t pop out when milk goes bad.
The indent also helps manage temperature changes. In summer, when plastic shrinks, it allows room to prevent overflow; in winter, it slightly adjusts but always ensures you get the same amount of milk.
Experts say the design keeps production costs down by preventing leaks and maintaining a fuller look on shelves—important for both safety and sales.
