Isoprop is an effective bacteriocial only at higher concentrations (i.e. 70% used in prep-pads), so I doubt it does much for 'glop'. A thin layer of isop floated atop gelled glop does provide a barrier against critters - it can be poured off before use.
There are plenty of beasties that thrive in full sunlight, so I doubt a typical exposure is going to have a major disinfectant effect. Post-printing hardening with an aldehyde will sterilize a carbon print, it was a fairly common practice in the "old days"