GLOBAL CHALLENGES

RFID Tags + MEMS Sensors Track Food for Safety

R. Colin Johnson | Date: 10-01-09 | Comments

In the October issue of the Journal of Food Science, researchers detail the range of future uses for RFID tags in the trillion-dollar food industry which employs about 17 million people in the United States alone.

When you see a "today's special" sticker on meat at the grocer, its hard not to imagine that the sale was prompted by a clerk leaving the meat out of the refrigerator too long. With radio-frequency identification (RFID) tags in the package tracking temperature, your fears could be allayed, according to the Institute of Food Technologists (IFT) which features RFID tag use in this month's issue of their flagship publication, the Journal of Food Science. In the October issue of the JFS, researchers detail the range of future uses for RFID tags in the trillion-dollar food industry which employs about 17 million people in the United States alone.

RFID tags are most familiar as the cause of that annoying buzz at the front door of retail stores. As you walk out the door, scanners "ping" the items you are carrying with a radio frequency signal tuned to the wavelength of their RFID tags. Any items that have not had their RFID tags removed by the checkout clerk will return an "alarm" signal, which sets off that annoying buzzer as you walk through the door.

The remarkable thing about RFID tags is that their antennas can collect enough energy from a reader's ping to turn-on, take a measurement and transmit the results back to the reader. Thus no battery needs to be installed in the RFID tag, making them very inexpensive. The twist that the Institute of Food Technologists recommends is adding sensors to track specific parameters relevant to food--like its temperature.

"We are using RFID tags to track temperature as food goes through a processing system," said professor K.P. Sandeep at North Carolina State University, an author cited in the JFS. "We designed a MEMS temperature sensor so small that we can put it inside food particles with an RFID tag. Then as the food goes through our process, we can log its temperature at each step, which helps us to get FDA [Food and Drug Administration] approval for a new process."

Micro-electro-mechanical systems (MEMS) are tiny mechanical devices that work without power too, making them the perfect mate for RFID tags. To get FDA approval for a new food process, Sandeep's team designed tiny millimeter-sized temperature sensors based on its MEMS plus RFID technology.

Another use of RFID tags that the Institute of Food Technologists recommends is tracking food products during distribution and storage. Then if there is a problem, every step between a product's shipment--from warehouse to retail shelf--can be read-out from the item's packaging.

Also by tracking temperature, humidity and other relevant parameters at every step in the supply chain, RFID tags can also enable the calculation of an "intelligent shelf-life quotient" that takes into account the conditions under which the food was stored.