Partially freeze pork. Slice across the grain into 1/4-in. thick strips; set aside. Combine broth, soy sauce, cornstarch and ginger; set aside. In a large skillet that has been coated with cooking spray, stir-fry pork and garlic for 5 minutes or until lightly browned. Add carrots, celery, onion, cabbage and spinach; stir-fry for 3 minutes. Add broth mixture; cover and simmer for 3 minutes.