The anecdotal evidence says it doesn't corrupt (begin smelling bad when stale).
I wonder if it has anything to do with common use of silver vessels and utensils in church, because silver ions do kill pathogens...
A lot of people customarily drink it as healing water, among other uses. Or they sprinkle the house with it for sanctification, actually the priest does, it's supposed to sanctify and banish demons from what it touches, some Charismatics have similar uses for anointing oil they prayed over. (I am not as familiar with Catholic use so I apologize for eventual misrepresentation, but this is what I know the Orthodox do.)