The milk carton that changes color before expiring

What a great idea designer Ko Yang has had with this milk carton that changes color telling us how fresh the milk is. The carton begins being white in color, and as the expiry date moves closer, it begins changing color to tell us we should drink the milk before it’s too late.
A brilliant way to help us consume our food without wasting any, something to which other idea-tors have already given some thought: 
(31999) Expiry date for products that have been opened 
(2255) Visual warning for expiry of food products