Six months ago, grocery staff at a North Center Trader Joe’s filed for a union election. The move came amid a swell of union organizing that swept the service industry over the last several years, hitting big names such as Starbucks and Apple and REI. At Trader Joe’s, grocery staff said they saw a union as a way to secure better pay, benefits and a bigger say in their workplace. When the Chicago workers voted in a union election in April, National Labor Relations Board officials counted 70 votes for the union and 70 votes against the union. One ballot, which belonged to a pin-wearing union supporter, wasn’t counted. For months, Trader Joe’s and the union fought over whether the ballot, which belongs to 25-year-old Brandi Hewitt, was valid.