User blog comment:DarkIngRidley/Cream in ''Survival of the Fittest''/@comment-4920092-20120523182235

By "target" they mean kill. He was planning on killing everybody who wouldn't produce the optimal meal. This way, when the survivors breeded, their offspring would likely have the traits Roman wanted.

Essentially, the Additive was chemically designed to kill people with certain genes. If someone without those genes drank it, they would be fine.