Chill-On Develops Prototype RFID-Enabled Time-Temperature Indicator

By Rhea Wessel

Nov. 15, 2007—A group of partners in an E.U.-backed project known as Chill-On has designed an electronic component that makes it possible to connect time-temperature indicators (TTI) to RFID transponders. The prototype component is the first step in long-term efforts to design a TTI that can be attached directly to an RFID transponder. Once refined, the prototype component should enable cold-chain participants to remotely monitor the shelf lifes of goods based on temperature exposure during shipment.

TTIs work with color-forming, proton-transfer crystals activated by ultraviolet radiation. Depending on the temperatures of its surroundings and the amount of time it has been exposed to those temperatures, a TTI changes colors, enabling a worker to determine if a product has been subjected to improper temperatures. The Chill-On consortium has also developed a TTI utilizing both color changes and an electrical signal to express temperature history. The prototype component can transfer that electrical signal and the temperature information from the TTI to an active RFID tag. Eventually, researchers hope to use the component on passive tags as well.

Upon interrogation of the tag, the temperature information is sent, together with the tag's unique ID, to the reader. This allows cold-chain participants to calculate the remaining shelf life of specific goods, based on the temperature information.

The Chill-On project is currently working to develop a way to monitor food constantly as it is shipped, whether chilled or frozen. Work is divided into seven work packages (WP): WP 1—Risk Assessment and Socio Economic Studies; WP 2—Biosensors for Low-Temperature Microorganisms; WP 3—Chilled Transport and Storage—Supporting Technologies; WP 4—Chain Information Management System; WP 5—Integration and Validation—Field Trials; WP 6—Training, Education and Dissemination; and WP 7—Management and Coordination. The RFID-related research falls under the Chain Information Management System package. The partners have declined to provide further details regarding how the prototype component works, but indicate it is presently too large to be integrated with an RFID transponder, such as a smart label for use on food.

"The main limitation within the food industry is the pricing," says Mark Lohmann, project manager for the Technology Transfer Center (TTZ) in Bremerhaven, Germany, the institute managing the Chill-On project. "Currently used RFID smart labels cost 5 euro cents [$0.07], and the forecast is that these costs will be reduced to 1 cent for bulk packaging by 2010."

If project members succeed in reducing the size of the component and adapting it to passive RFID technology, Lohmann says, the device could be used widely within the food supply chain and, thus, dramatically lower the cost of using temperature sensors in combination with RFID. Standard TTI labels are currently available for only a few cents apiece.