Walmart is being sued by a Silicon Valley company that says the largest U.S. retailer stole its technology to prolong the shelf life of produce.

Zest Labs and its parent filed a $2 billion complaint yesterday saying Walmart’s “Eden” technology to preserve fruit and vegetable freshness “looks, sounds, and functions” like its own Zest Fresh technology, according to Reuters.

Zest said it had worked with Walmart for years on Zest Fresh before the retailer lost interest last November. The company said it was “stunned” in March when Walmart claimed to have developed Eden internally over six months through a “hackathon” among its own engineers, and that it had prevented $86 million of waste so far.

The complaint said Walmart used its years of unfettered access to plaintiffs’ trade secrets, proprietary information, and know-how to steal the Zest Fresh technology and misappropriate it for Walmart’s own benefit.

Walmart says it will respond to the complaint in court.

Zest said Walmart has estimated $2 billion of savings over five years from Eden, and said the retailer could save $15 billion over a decade.

Its lawsuit seeks to recover such savings for Walmart’s alleged theft of trade secrets, unfair competition, breach of contract and other wrongdoing.