He had indeed noticed all the details Leng Pan had mentioned but he hadn't expected them to be so important in distinguishing between human children and zombies.
"Don't take it as if only children have that ability. If adult zombies become stronger, they could also create illusions of having healthy skin like that of humans. If you only base identifying zombies on their rotten flesh, you might have a problem in the future when the zombies become stronger.
But even so, I don't think that their thirst for blood and eating human flesh can change, so, be careful. I also think that even if they know how to hide their human flesh, there will always be clues. You just have to be careful." Leng Pan continued to explain hoping that the information will be of some significance to her family.