At a recent event for the American Chemical Society, Chinese researchers presented food labels that change color when food has gone off. This could seriously save some poor souls who just aren't sure whether or not the milk is still good.
The small squares can be adjusted depending on the food involved, but the main innovation is how these tiny products change when detecting any form of rot developing on the perishable good. The tags can be added onto a product, and there is also the possibility that these tiny devices could be used to see whether or not medication is still usable.
These food labels could eradicate the entire "smell test" experience when checking products in the fridge.