According to Mother Jones, Big Dairy is putting little bits of metal in dairy products to make it look better. Brighter whites is not just for laundry anymore! And I guess folks associate those brighter whites with better taste and more nutrients.
Dairy manufacturers are taking historical, visible markers of quality and mimicking them while decoupling them from the underlying qualities that made the markers worthwhile. This is why a tomato bred for red color (and not taste) ends up looking way better than it tastes.
All this is just an application of the rule that if you apply metrics, the reaction will be to maximize those metrics even in the face of absurd results. Be careful what you measure!