Researchers from the University of California, Berkeley (UC Berkeley), along with colleagues at Taiwan’s National Chiao Tung University, have developed a 3D-printed cap smart cap to detect spoiled milk.
The 3D-printed cap uses embedded sensors to wirelessly detect signs of milk spoilage.
The researchers have used polymers to create electronic devices due to their flexibility that allows them to be formed into a variety of shapes as needed for 3D printing.
The shape and design of the metal determined the function of different electrical components.
Since the polymers are poor conductors of electricity, the researchers decided to develop a system using polymers and wax. The wax was then removed, leaving hollow tubes into which liquid metal was injected and cured.
By changing the shape of the metal, the researchers integrated the electronic components into a plastic milk carton cap to monitor the freshness of milk.
The researchers said that a quick flip of the carton allowed a bit of milk to get trapped in the cap's capacitor gap, and the entire carton was then left unopened at room temperature for 36 hours.
The circuit could detect the changes in electrical signals which is due to changes in milk as bacteria level increases.
Berkeley Sensor and Actuator Center co-director Liwei Lin said: "This 3D-printing technology could eventually make electronic circuits cheap enough to be added to packaging to provide food safety alerts for consumers.
"You could imagine a scenario where you can use your cellphone to check the freshness of food while it's still on the store shelves."
