In a medium-size mixing bowl combine thoroughly the meat, onion, garlic, egg, and turmeric. Leave in refrigerator overnight. Next day, divide meat into 20 equal portions. Cut lemon grass into 8-inch lengths. Press meat around each lemon grass kabob. Place over hot barbecue or griddle each side for about 5 minutes. You can also line a pan with foil and broil the koobideh under high heat. Serve with basmati or jasmine rice or over soft flatbread. Sprinkle sumac on top of pork before serving. Pour cooking juices over the rice or bread.