According to grocery industry estimates, one US$100 supermarket trolley, or cart, goes walkabout every 90 seconds in the US, theft that is costing retailers millions of dollars a year.

Gatekeeper’s new device is offering to put a brake on trolley theft, however, by effectively freezing the cart’s wheels when it is taken towards a set perimeter of the store. The wheels can only be released by a specially designed ‘key’.

Several stores have been testing the device for months, creating a force field with underground cable marking the edge of the supermarkets’ property, and its developers say it is now ready for a more general release.

Lee Brunson, spokesman for Publix Super Markets, said the trial was a successful and the device “helped us tremendously”. Winn-Dixie is meanwhile testing the device in a few Orlando locations, complaining that people do not seem to appreciate that taking a trolley is actually classed as criminal theft.

Brett Osterfelt, VP at Gatekeeper, commented: “Shopping carts are expensive. Replacing them starts to eat into your profits pretty quickly.”