This article will introduce to you how RFID sensors are applied to detecting food quality and monitoring food safety.

Radiofrequency identification (RFID) sensors are finding their diverse applications when an unobtrusive sensor form factor, battery-free design, and minimal sensor cost are the top three requirements for a new sensor. Examples of diverse applications include pharmaceutical, warehousing, agricultural, industrial, food safety, and security.

Benefits of RFID sensors for food quality and safety, as compared to tethered sensors, include the non-obtrusive nature of their installations, higher nodal densities, and lower installation costs without the need for extensive wiring.In addition, a significant advantage of RFID and other electronic sensors over optical sensors is in the ability to perform measurements through non-transparent packaging.There are several developed battery-free wireless sensing technologies based on magnetoelastic,16 thickness-shear modes, surface acoustic wave, magnetic acoustic resonance, and resonant LCR (inductor-capacitor-resistor) transducers. Several approaches for battery-free RFID sensing have been explored, e.g. based on chipless RFID sensors.
We recently developed a methodology to implement passive RFID tags for physical, chemical, and biological sensing. In our RFID sensing approach, the resonance impedance spectrum of the sensor antenna is measured and further correlated with the chemical, biological, or physical properties of the environment. This correlation is performed using the multivariable response of the RFID sensor computed from the measured impedance spectrum.
The complementary driving forces in successful sensor development are innovative ideas and the market size for new sensors. The market size is often but not always is supported by the regulatory requirements. If both driving forces are strong, the sensor development moves from its initial proof-of-concept technology readiness level to the commercialization of the sensor technology.
The sizes of markets for food safety testing products ($0.25 B) and pathogen detecting sensors ($0.5 B) and provide exciting opportunities for the development of new sensing technologies for food quality and safety.
Intelligent labeling of food products to indicate and report their freshness and other conditions is one of the important possible applications of the developed RFID sensors.
Unlike other food freshness monitoring approaches that require a thin-film battery for operation of an RFID sensor and fabrication of custom-made sensors, our developed passive RFID sensing approach combines advantages of both battery-free and cost-effective sensor design and offers response selectivity that is impossible to achieve with other individual sensors.
In this review, we summarize the result of the development of RFID sensors for food quality and safety. In these sensors, the electric field generated in the RFID sensor antenna extends out from the plane of the RFID sensor and is affected by the ambient environment providing the opportunity for sensing.
This environment may be in the form of a food sample within the electric field of the sensing region or a sensing film deposited onto the sensor antenna. Examples of applications include monitoring of freshness of milk, the freshness of fish, and bacterial growth.

Example of Applications

    · Monitoring of milk freshness

    · Monitoring of fish condition

    · Direct monitoring of bacteria growth