Us oldfags grew up when this was pretty much Common Sense. Put good stuff into your bodies, build up Immune System. Now there are hypochondriacs who run to the Dr. & pharmacy for every damn minor thing and become immune to Antibiotics, etc., and can't NATURALLY fight off anything - even a cold.
Now, even restaurants will have to go back in time and "teach" people the most basic of basics, such as good ol' Common Sense Sanitary practices.