Edible Antibiotics in Food Crop

A large land-grant institution and a major agricultural company have teamed together to create a variety of corn that has been bioengineered to create large quantities of penicillin. The developers believe that this new crop will help drop the cost of the drug, and make in more available to the populations of developing nations. Opponents of the GM crop have raised a number of issues including the possible contamination of other varieties of corn. What are some of the ethical issues at stake in this case?