More than 1,000 Starbucks baristas at 75 U.S. stores have gone on strike since Sunday to protest a new company dress code, a union representing the coffee giant's workers said Wednesday. Starbucks put new limits starting Monday on what its baristas can wear under their green aprons. The dress code requires employees at company-operated and licensed stores in the U.S. and Canada to wear a solid black shirt and khaki, black or blue denim bottoms.