PHILADELPHIA (AP) — Hundreds of food service workers at the Wells Fargo Center in Philadelphia were staging a one-day strike Tuesday as contract negotiations continued with the firm that operates concessions at the stadium.

Roughly 400 cooks, servers, bartenders, concession staffers and other members of Unite Here union local 274 started picketing early in the day in the arena’s parking lot, several hours before the Philadelphia 76ers were due to play the Detroit Pistons in an NBA game. The workers were urging fans to not buy food, drinks or concessions from Aramark and eat elsewhere instead.

The union — which represents people who work at the Wells Fargo Center and neighboring Lincoln Financial Field and Citizens Bank Park, where the Philadelphia Eagles and Philadelphia Phillies, respectively, play — say their wages and benefits are not keeping up with inflation. The union said some staffers who work at all three stadiums make different hourly wages at each site, and union members say they are treated as seasonal workers rather than year-round employees, based on each sport’s season.

Randi Trent, a caterer with Aramark for 23 years, was among those manning the picket lines Tuesday.

“I’m out here fighting for health care for everyone. They need better wages. We all need (better) wages across the board,” Trent said. “I make $8 an hour. We work off of gratuities. Our percentages are low.”

Chris Collom, an Aramark spokesperson, said the company “remains committed to bargaining in good faith to reach a settlement that works for all parties.” He said the firm had contingency plans in place to ensure its services were not interrupted at Tuesday night’s game, but he did not disclose specific details.