Someone brought up the subject of what effect juice might have if it got on the leather so I did a little testing.
I placed a single drop of a medium-dark, fairly acidic fruit-flavored juice on each of my color samples. After an hour of sitting, none of the juice had soaked into the leather at all, so I gave each sample a quick wipe with a cotton cloth to remove the standing juice and then let them sit overnight. In the morning i gave each sample a light rubbing with a damp cloth.
All of the samples show some degree of discoloration but it seems to be the finish that is damaged by juice since it doesn't seem to be actually getting into the leather. I think that, had the juice been wiped away immediately, there probably would not have been any discoloration at all.
It would probably do more damage if a significant amount of juice were to be absorbed into the unfinished back of the leather, but even water absorbed into the back can discolor the front slightly, even once it's dried out.
So, the moral of the story is "Don't get liquids on your holster and, if you do get liquids on your holster, clean it off right away".