Saute bacon in heavy kettle. Add cabbage, onion, celery, carrots, potato and zucchini; reduce heat and simmer about 20 minutes. Add tomatoes, beef broth, barley, and rice; simmer 2 hours. Blend in white sauce, vinegar, garlic, caraway seed, salt, Worcestershire, and thyme. Simmer about 15 minutes. Adjust seasonings if necessary. Garnish with sour cream and serve. Serves 6.