Sensor detects water adulteration of honey

Researchers in China say they have developed a compact, low-cost and easily manufactured sensor that can detect adulteration of honey, one of the foods most vulnerable to food fraud.

The team from the Nanjing University of Aeronautics and Astronautics and the Hebei University of Technology have developed what they describe as a “microstrip line planar resonator sensor” that can detect when honey has been adulterated with water – the most common form of honey fraud but one that is hard to detect with conventional testing.

“When we add water to honey, it changes how the electromagnetic field behaves around it,” said Zhen Li lead author of a paper describing the sensor that has been published in the Review of Scientific Instruments journal.

The microstrip line resonator sensor is fabricated on a dielectric substrate, which is an insulator that can efficiently support electrostatic fields, such as ceramic or glass. On top there are three thin copper strips separated by two gaps. The length of the middle strip and the electric field intensity at the gaps determine the resonance frequency of the device.

Image credit: Qi Jin, Zhaozong Meng, Zhijun Chen, and Zhen Li

“When placed in the sensor, adulterated honey shifts the sensor’s resonance frequency. By measuring this shift, we can detect water adulteration in honey,” according to Li, who said the device – which can also give a quantitative assessment of adulteration – could become “a cost-effective and efficient method for the food industry to ensure honey authenticity.”

“We aim to extend our research to detect adulteration in other liquid products and develop more sensitive sensors for broader applications in quality control and food safety,” added Li.

Main image courtesy of Institute of Physics