The Hope Centers were an international government cooperative effort to reduce world hunger in the Zombie Multiverse.
At least, that was their official purpose.
Their true purpose was to develop a gas that turned people into flesh-eating Zombies in what was known as, "Operation Sweet Death". This was to curb world hunger by curbing over population - at least, in the Third World.
When one located in New Guinea suffered from containment failure, Lt. Mike London's SWAT team was sent in to kill the zombies. More often than not, the damage had already been done, and the Zombies made it to developed countries.