Scratch and sniff.

Scouring the produce section for that perfect, mouth-watering fruit? Squeeze and sniff no more. New Zealand scientists have invented high-tech packaging with color-changing labels to show when fruit is ripe.

Plants produce fruit as a way to spread their seeds for reproduction. When fruit is mature, it broadcasts its lusciousness by releasing organic chemicals (molecules containing carbon atoms as their backbone), which attract hungry animals. Scientists at HortResearch spent five years developing a sensor that responds to the pleasant-smelling chemicals, known as aromatic compounds, given off by fresh fruit.

The hands-off labels, called ripeSense[TM], change color as their built-in sensors react to the fragrant chemicals released by the ripening fruit. "You could say these are labels with a sense of smell," says Kevin Moffitt, of Pear Bureau Northwest, which recently tested the labels on pears.

U.S. stores could see ripeSense-labeled pears within a year. And as scientists develop sensors for other fruits, the days of mango mangling and peach-pinching may soon be over.