Berkeley’s new electronic nose recognizes food odors and signs of spoilage.
UC Berkeley researchers built a proof-of-concept electronic nose that detects gases from spoiled food and common allergens such as walnuts and peanuts, and they report it outperforms the human nose.
Researchers at the University of California, Berkeley have developed an electronic nose that can detect gases given off by spoiled food as well as the presence of common food allergens, according to the university. The device is described as a proof of concept. The study appeared June 17, 2026, in the journal Science Advances.
The device is built from an array of 16 small gas sensors. Each one carries a different sensing film and responds to a slightly different combination of gases, converting chemical reactions at its surface into electrical signals. Lead author Carla Bassil, a Ph.D. student in electrical engineering and computer sciences, trained a machine learning model to recognize the response patterns for seven foods: strawberry, blueberry, banana, walnut, hazelnut, cashew and peanut. She also trained it to identify raw chicken, milk and eggs when fresh and after 24 and 48 hours at room temperature.
In testing, the nose detected 0.05 grams of isolated walnut, roughly one hundredth of an average shelled walnut. Bassil has not yet tested the device where other gases are present, such as walnuts in a salad or cake, or spoiled food stored alongside other foods in a refrigerator. She described the result as a chip that is "far more sensitive and far more objective than any human nose can be."
Electronic noses have existed as a concept since the 1980s, but putting many different sensing films on one chip has been difficult. Bassil used carbon nanotubes rather than metal oxides as the conducting material. Because the nanotube layers work at room temperature, she could choose from a wider range of materials, including polymers that might break down under heat. That also let her make the chip by drop casting, a simple process.
Bassil has since built a portable version that can be operated with an iPhone app, though it was not part of the study. She plans to test the next generation in more varied environments while improving sensitivity and reliability, and she suggested smart refrigerators as one possible use. Ali Javey of Berkeley is the senior author, and coauthors come from Berkeley and KAIST.
At a Glance
- The electronic nose uses an array of 16 gas sensors, each with a different sensing film.
- The study was published June 17, 2026, in Science Advances.
- The device detected 0.05 grams of isolated walnut, about one hundredth of an average shelled walnut.
- Raw chicken, milk and eggs were tested fresh and after 24 and 48 hours at room temperature.
Sources
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