Have you ever drunk milk that’s not exactly fresh? I have one time, and you can bet that it was a long time before I’d even touch the stuff again. That was especially rough because I’m the kind of guy that can live off of cereal, which is no good without milk. Those expiration dates are helpful in telling you when the milk is bad, however, there are other factors that can contribute to making the milk go sour, which is why a cool little gadget was created that can tell you if the milk is good or bad.

The gadget has two parts, one that goes in the milk container, and another outside that can let you know the status of the milk. The bit inside the milk container is actually just a slim metal ribbon. The detector creates a magnetic field that causes the ribbon to vibrate. If it vibrates too slowly the milk is sour, too quickly and the milk has Staphylococcus aureus. Unfortunately these systems only work inside the store. When you take it home, just keep it in the fridge and check the expiration.

Source: CrunchGear