Workers suing General Mills Inc. for age discrimination won a round in federal court when a judge rejected the company's attempt to dismiss the suit and compel individual arbitration.

The suit, filed earlier this year in Minneapolis, stems from a General Mills corporate restructuring in 2012 that led to about 850 mostly white-collar layoffs.

The suit's 33 plaintiffs, all aged 40 and above, claim they were improperly terminated in violation of the federal Age Discrimination in Employment Act. The layoffs affected older employees at much higher rates than younger employees, they claim.

Golden Valley-based General Mills says the plaintiffs signed severance agreements that waved legal claims under the age discrimination act. Also, the agreements called for any disputes to be settled through individual arbitration.

However, the plaintiffs argued that the employees' release agreements were not signed "knowingly and willingly," and therefore unenforceable.

Whether a waiver release is signed ''knowingly and willingly" is a matter to be determined in court, as spelled out in another federal law, the Older Workers Benefit Protection Act [OWBPA], according to a ruling Friday by U.S. District Court Judge John Tunheim.

The law "clearly mandates that a dispute over the validity of a waiver of substantive claims or rights under the OWBPA, like in this case, shall be heard in court, not an arbitral forum," Tunheim wrote.

General Mills plans to appeal Tunheim's ruling. "The judge's decision was narrowly focused on whether these claims should be heard in court or in arbitration," General Mills said in an e-mail to the Star Tribune. "We continue to believe these claims should be resolved in arbitration."

The federal Equal Employment Opportunity Commission and the AARP both filed friend of the court briefs opposing General Mills' motion to dismiss.

The Older Workers Benefit Protection Act, among other things, made it harder for companies to "cajole" terminated employees into giving up their rights under federal age discrimination law — "especially in the context of a large-scale group layoff, in which individual employees have little-to-no leverage," Tunheim wrote.

The suit's 33 plaintiffs have an average age of 52 and had been with General Mills for an average of 20 years, court documents show. They were terminated as part of Project Refuel, a 2012 cost cutting-program that led to about 850 layoffs, about half of which were in the Twin Cities.

Over the past year or so, General Mills has laid off at least 2,500 people, dogged by soft sales vexing the packaged food industry. Those layoffs included Project Catalyst, which covered up to 800 white-collar workers, many of whom worked in the Twin Cities.

General Mills employs around 5,000 in the Twin Cities.

Mike Hughlett • 612-673-7003