In the early 1900s, Imogene Rechtin started a crusade to get people to stop kissing socially as a way to stop disease spread. Her argument was sound, but she was largely dismissed as being uptight.
Research:

Percy Fawcett, Manuscript 512, and a Lost City in the Amazon, Pt. 2
37:10

Percy Fawcett, Manuscript 512, and a Lost City in the Amazon, Pt. 1
34:05

SYMHC Classics: Swill Milk
39:22