Italian Beef Pasta

1 pound beef tenderloin, cut into thin strips
1 tablespoon vegetable oil
1 onion, chopped
2 cloves garlic, minced
3 red bell peppers, chopped
1 zucchini, chopped
2 tomatoes, chopped
1/2 pound sliced mushrooms
2 teaspoons Italian seasoning
2 cups beef broth
1 tablespoon cornstarch
1/4 pound rotini pasta

In a large skillet over medium heat saut