RFID advances help food traceability

By Ahmed ElAmin

- Last updated on GMT

Advances in RFID make the technology more useful to food processors
in tracing and tracking their products.

The advances include such developments as longer range password protected tags, ones that are tolerant to high-temperature and sterilisation, and devices that work well with substances such as metals and liquids.

More and more retailers are pushing their suppliers to use RFID as a means of tracking products more efficiently through the supply chain.

However the relatively high cost of the technology and the difficulties in making the switch has held back many companies from introducing RFID in their plants and supply chains, according to a report by Peter Harrop, chairman of IDTechEx.

RFID is a method of identifying unique items using radio waves. Typically, a reader communicates with a tag, which holds digital information in a microchip.

Harrop says many countries limit the frequency at which RFID can operate, thus making it difficult to read tagged objects at a distance greater than one metre.

A longer range has always been available if there is a battery in the RFID tag. However, the so-called active tags have limited life and are expensive, relatively large and with more parts to go wrong.

That has meant that UHF passive tags have had to be standardized for pallets and cases of food and other produce. Although UHF RFID works reasonably well with nothing in the way, the technology can behave very unpredictably when water or metal is nearby, Harrop stated in his report.

Improvements to UHF systems are coming along but there is also help in prospect from recent advances in the traditional high frequency and microwave systems. The advances make the technology useful at longer ranges and more suitable for traceability applications.

One development is the use of the high frequency (HF) range, which extends the range at which tags can be read, sometimes even to ten metres.HF tags are more tolerant of water and metal than those at UHF, and thus provide greater reliability.

Companies have also developed the Surface Acoustic Wave (SAW) chip to replace the silicon chips in RFID tags. SAW chips have no threshold voltage. They can sense temperature without additional sensors and they are inherently simpler to make.

SAW RFID has been around for some time, benefiting from reliability and the cost reduction that comes from the billions of non-RFID SAW chips used in mobile phones and pagers.

The unique physics of SAW ID chips solves major RFID issues. They can be reliably read at large distances and surmount the tendency of liquids and metals to block reading signals. They can also be used for full pallet reading, a vitally important RFID capability, Harrop stated.

"In many applications, SAW tag read range is sufficiently large so that passive tags can replace high-cost battery-powered active tags,"​ he stated. "SAW-based RFID systems have the inherent ability to measure tag position, direction of travel and tag temperature, which are costly or difficult to implement with competing technologies. Furthermore, SAW tags can withstand security and safety related processes that involve elevated operating temperatures, high energy x-rays, or gamma ray sterilization as is used with some food and medical supplies."

RFSAW Global has developed a SAW tag that uses an inherently lower cost chip in combination with a smaller, less costly tag antenna. Costs are further reduced by placing key signal processing functions such as multi-tag reading in the reader unit instead of the tag.

Unlike UHF, it can operate legally worldwide today. There is no need to await regulatory clearance, whether they are being used in Europe, the US or China.

Companies such as Samsung, Thoronics and Carinthian Tech Research have recently developed SAW RFID tags able to tolerate and monitor temperatures in engineering and industrial applications.

Some of the new technology is currently being used by industry. For example Icelandic Fisheries successfully used HF for wet fish in pallets and cases because UHF did not work at the range the company needed.

Another development is the password-protected HF tag, such as the one introduced by Texas Instruments. Password protection is being used mainly on pharmaceutical products but could apply to the food industry, Harrop stated.

Eventually, item level tagging of food in the supermarket will have to involve tags staying on after the till and not being deactivated. IDTechEx finds that 30 per cent of the potential benefits and paybacks at item level occur after the till, including better recalls, fraud reduction and providing consumer rewards.

Last year Wal-Mart, the world's largest retailer, announced it would require its top suppliers to implement RFID. In Germany, Metro has an ambitious programme to use RFID for all products to the point of sale.

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