How do similar yogurt products compare in terms of additives?

Yogurt mass-producers such as Dannon and Yoplait offer yogurt products that have potassium sorbate added, "to preserve freshness," as the label often indicates.   This additive is frequently found in more processed items such as drinkable yogurt smoothies and "creme-style" products. Potassium sorbate  extends the product’s shelf life; it is a chemical preservative, primarily a mold inhibitor. It also helps to maintain  consistent freshness during storage.  
 
Some manufacturers, (for example, Stonyfield Farms) use organic milk and do not add preservatives. 
 
Source(s): 
Dannon recorded consumer help line:  1-877-DANNONUS
Interview with Dannon consumer relations representative.  (name not recorded)