The next generation of smell sensors could remove the need to sniff milk to see if it has gone sour.
Researchers at Stanford University are working on sensors capable of identifying anything from explosives to milk on the turn.
They are produced using the same process that allows scientists to synthesis DNA and represent a generational step forward from their equivalents.
Existing sensors for aroma can detect a single compound and alert the user to its presence.
However, the Stanford team is working on colour-based systems in which a different hue is selected depending on which chemicals are found, allowing multiple traces to be identified.
They hope to develop a smell-activated device suitable for mass production as an "artificial nose" for a wide spread of electronic detectors.
Illinois-born professor of chemistry Eric T Kool leads the research team at Stanford, where he has had a laboratory since 1999.