Mild cheese flavor in reduced fat Cheddar cheese was enhanced by using an integrated starter culture system. Three cultures, Lactococcus lactis subsp. cremoris SK11, L. lactis subsp. lactis biovar. diacetylactis JVI, and Lactobacillus casei 7A, were carefully selected to obtain a nonbitter, mildly acid, buttery flavored cheese. Cheeses were produced from all possible combinations of these cultures with the constraint that L. lactis subsp. cremoris SK11 was used as the primary acid-producing culture. Cheeses made with SK11 were compared to cheeses produced using an L. lactis subsp. cremoris commercial starter culture. Cheeses were ripened for 150 days and periodically sampled for chemical, microbiological, and sensory analysis. Cheeses produced with L. lactis subsp. cremorisSK11 had substantially lower bitterness intensity than the cheeses produced with commercial starter culture. L. lactis subsp. lactis biovar. diacetylactis JVI significantly increased diacetylacetoin and acetate concentrations. Sensory results indicate that these cheeses had increased buttery (diacetyl) flavor.