More than 500 workers at a General Mills cereal plant in Cedar Rapids, Iowa, voted this week to unionize in hopes of protecting wages and benefits.

The 520 nonsalaried plant workers will now be represented by the Retail, Wholesale, and Department Store Workers Union (RWDSU), which also represents workers at the Quaker Oats plant in Cedar Rapids.

“Everyone is still very grateful and thankful for our jobs at General Mills,” said Tim Sarver, a worker at the plant for 36 years. “We decided to organize a campaign after … we noticed there had been a trend over the years of slowly having benefits cut away.”

General Mills, headquartered in Golden Valley, has owned the plant for 49 years. It makes cereal, fruit snacks and desserts at the site. Company spokesman Rob Litt said the company has a great relationship with the plant’s workers.

“We respect our employees’ right to make this choice and will work to have a productive relationship with the [union],” the company said in a statement.

Over the years, RWDSU has been in contact with small factions of the plant’s workers, but the latest union talks began in earnest about four months ago, said Roger Grobstich, vice president of RWDSU International.

Sarver said workers noticed a gradual whittling away of their benefits. They were also concerned about the company’s growing use of temp agencies in supplying cheap labor that the General Mills plant workers feared would undercut, and one day, result in the elimination of their jobs. A recent change to the attendance policy — reducing the workers’ absences from five to three days a year — was the final blow, pushing the group to organize.

General Mills this summer expanded its short-term disability program, parental leave and family caretaker policies. As a result, the company said, there were changes made to other leave programs at some locations.

Nearly 60 percent of the plant’s production, sanitation and maintenance workers voted for unionization Wednesday, Sarver said.

Organizers laid out guidelines for a “respectful campaign,” he said, promising the anti-union workers they would never hand out fliers outside the gate or call workers at their homes.

“We are a very special plant. Through the process, there was no disrespect to either side,” Sarver said. “Our goal is to put out great products for Mills and to make the company and all of Cedar Rapids proud.”

General Mills employs about 40,000 full- and part-time workers, both union and nonunion, globally. Last spring, the company eliminated 625 positions, through both layoffs and not filling open jobs. But the company also created new positions in different areas during that period, Don Mulligan, chief financial officer of General Mills, said at that time. That came more than a year after General Mills wrapped up several multiyear cost-saving initiatives that led to more than 5,000 job cuts.

There are other unionized General Mills plants, though the company wouldn’t specify how many of its employees are union members.