How do I handle old Japanese people touching my toddler and baby’s face?

Every time I am out with my kids old Japanese men and women like to come up and say hello which I don’t mind at all but I do not like when they touch my kids face! I am not a confrontational person and I don’t speak much Japanese so I’m not sure how to handle it. They do it almost every single time. Is this even normal? My kids are mixed and I don’t ever see them doing this with other people’s babies but mine.

I really hate it because a lot of people here sneeze and coughs on their hands. And In America touching someone else’s baby without permission is considered very rude.