Rotten milk must be the most disappointing thing in the world; unless you have another carton lurking in the back of your fridge. Small sensors could change your morning disappointment in the future, with information about the milk's quality.
It'd make cartons of milk a heck of a lot more expensive, sure, but displaying the condition of the contents on a mini screen could alert you to buy more milk the next day, or even to toss the whole carton out if the milk's off.
Research undertaken by a physics student at the Finnish university Abo Akademi has shown that you could even have simple puzzles and games on the side of the carton as well, or in Harry Potter-style, moving images of a missing child (like cartons of yesteryear used to display.) There are just a few obstacles before these cartons could be mass-produced however, aside from the cost, mainly in the area of the actual paper build. You'd still need it to be waxy enough so that it's not soluble, and hygiene issues need to be looked into too.
If it ever happens, it's not going to be for many many years, so it's probably still safest to just keep on doing the whiff-test each morning. [Discovery]