A dielectric loss angle based portable biosensor system for bacterial concentration detection

A new type of portable sensor is proposed to detect bacterial concentration based on the change in dielectric loss angle δ . The performance of the sensor is tested in four types of drinks, namely, milk, orange juice, peach juice, and tomato juice. Notably, the sensor can detect δ when the bacterial concentration reaches a critical threshold value (approximately 10 6 cfu mL −1 ) by applying a 1 V peak-to-peak 200 Hz sinusoidal test signal of 0.25 mA at intervals of 10 min. This work introduces a portable and low-system for rapid detection. The system is a useful tool for microbial screening in industrial and commercial environments. A new type of portable sensor is proposed to detect bacterial concentration based on the change in dielectric loss angle δ .