3D Printed Bottle Cap Lets You Know When The Milk's Gone Bad

Perishable food products such as milk have a relatively short shelf life. However given that milk is considered by some to be a staple, finishing a carton before its expiration date is usually not an issue. However sometimes dates could be mislabeled, or maybe you've forgotten, or maybe that batch of milk you got was bad. How would you know? Obviously drinking it and finding out isn't the smartest solution, which is why engineers from the University of California Berkeley and Taiwan's National C...