How does McDonalds keep the bags of apples in happy meals from turning brown?
Sliced apples will undergo browning within a few minutes of being cut. Packaged apples found at McDonalds or in your local produce section are usually treated with a solution of calcium ascorbate (a blend of calcium and vitamin C) or citric acid (found in citrus fruit) to maintain freshness and color. Both are very safe to use on fruit that will be consumed. To keep sliced apples looking fresh at home, try dipping in orange juice or other citrus juices to prevent the browning reaction.