It doesn't. "Sterile" means free from bacteria or other micro-organisms; totally clean.
o my goodness!
There are times on MN when I see such basic misunderstandings of science that I just have to keep on coming back and repeating myself.
Sterile means no bacteria.
If something nutritious is sterile it is colonised and contaminated very very fast.
if it is colonised by a pathogen, that pathogen will multiply many times faster than in the normal environment, because there is no other competition in that medium.
Think of agar in petri dishes.
It is used to identify bacteria in the environment because it is sterile, therefore one exposure of a second or less to the environment and you get to see colonies developing within hours, very fast, because it was sterile, and nutritious, as urine is.
Urine being kept for a few hours becomes a health hazard very quickly, Its not going to do you any harm if disposed of quickly and carefully in the morning and the container scrubbed out.
But pleas e don't confuse "sterile" with " antispetic"( which kills pathogens)
"sterile" doesn't kill pathogens, sterile and nutritious encourages them.
I have unfortunately come across mothers with this confusion about what "sterile" means before..