Sea Shell Crab Casserole

Ingredients

• 1 1/2 cups medium pasta shells
• 1 large onion, chopped
• 1 medium green pepper, chopped
• 3 celery ribs, chopped
• 3 tablespoons butter
• 1 (12 ounce) can evaporated milk
• 1/2 cup mayonnaise (reduced-fat and fat-free may not be substituted)
• 1 teaspoon salt
• 1 teaspoon ground mustard
• 1 teaspoon paprika
• 1 teaspoon Worcestershire sauce
• 1 (2 1/4 ounce) can sliced ripe olives, drained
• 2 (8 ounce) packages imitation crabmeat, flaked