Americans are becoming more health conscious, choosing food that is organic, packed with antioxidants and free of preservatives and antibiotics. So it is small wonder that McDonald’s, a global fast food juggernaut known for less-than-nutritious food, has seen sales stagnate. But the company recently decided to join the health-conscious bandwagon: This month, McDonald’s said it has completed a commitment to phase out the use of chicken raised with antibiotics used in human medicine at its U.S. restaurants. It also plans to remove artificial preservatives from popular items such as McNuggets and McGriddles. Sandwich buns will no longer contain high fructose corn syrup. But will diners buy it? Jason Riis, a Wharton marketing lecturer, and Sherrill Davison, associate professor of avian medicine and pathology at the University of Pennsylvania’s School of Veterinary Medicine, discuss McDonald’s latest strategy on the Knowledge at Wharton Show that airs on Channel 111 on SiriusXM .…