Across the country, the Service Employees International Union is trying to get employees of the food service company Sodexo to unionize.  It's been a heated battle, and it's made its way to the Lehigh Valley. Here are some of the facts. 1. Sodexo is one of the largest employers  in the world, with 120,000 employees just in the United States. In the Lehigh Valley, their workers handle food service duties at several local hospitals -- including Sacred Heart, Good Shepherd and Lehigh Valley Hospital Cedar Crest -- and colleges.  2. The SEIU is a large union, with 2.2 million members. SEIU 32BJ, …