On 1 January this year Wal-Mart introduced a system of radio frequency identification (RFID) tags on pallets and cases of merchandise going to 150 stores in the southern US.
Tesco has been testing similar devices in Britain. The tags currently track goods only en route from production to warehouse to store, but the technology could in future be easily inserted into any individual product - and thus tracked after purchase. One enthusiastic executive said recently, 'We'll put an RFID tag on everything that moves in the North American supply chain!' Genetically modified food is already widely tracked using RFID.