Some studies show that cut apples are more likely to be consumed by children than when they are given a whole apple. However, sliced apples undergo browning within a few minutes of being cut. Rinsing sliced apples with Calcium Ascorbate (a blend of Calcium and Vitamin C to maintain freshness and color) or dipping sliced apples in orange juice at home will prevent the browning reaction because it reduces exposure to oxygen. Calcium ascorbate is very safe and is used on most of the sliced apples that you find in your produce department, so McDonald’s apples shouldn’t taste any different than those. You can always simply cut apples yourself if this concerns you.