Cold Pesto Salad for 50

Ingredients
2 lb + 8 oz macaroni, small shells    
 5 lb Caligornia or Italian blend frozen vegetables    
 3 cups green onions, thinly sliced,    
 1 quart black olives, sliced, drained    
 2 cups parsley, chopped    
 1 cup tomato paste    
 1 cup dried basil    
 4-6 Tbsp garlic, chopped    
 1/3 cup canola oil    
 1 cup vinegar, preferably rice vinegar    
 5 1/2 oz grated Parmesan cheese    
 2 quarts plain low-fat yogurt    
 2 lbs fresh tomatoes, chopped

Directions             
Cook macaroni until barely tender. Rinse and transfer to a large mixing bowl. 
Let cool. Cook vegetables until tender. Drain and cut into bite-sized pieces if 
necessary. Let cool. Add cooled vegetables, onions, olives, and parsley to 
cooled pasta. Mix well.

To make the dressing, put tomato paste, basil, garlic to taste and Canola Oil 
in a food processor or blender. Blend, scraping often, until fairly smooth. Add 
vinegar, cheese and yogurt. Blend again. Pour dressing over pasta-vegetable 
mixture. Add tomatoes and mix well. Makes 50 servings.  

(Source: Healthwise Quantity Cookbook)