Basically I pitted and smashed 10 lbs. of very ripe plums; heated the pulp, skins and juice to like 120°F and added 3 gals. of distilled water and 5 lbs. of sugar. Waited for it to cool below 90°F then strained it into a bucket and added 1-2 tbsp. of bread yeast. Then put it in a carboy with an airlock, it has been only one day and the airlock is already bubbling madly. I am going to distill it in my pot still and hope for a delicious plum brandy. I am concerned about bacterial or mold growth but am not sure if I need to be. I am thinking it should be done fermenting in like a week. Do I need one of these additive tablets or will it not be a big deal because I will distill immediately after my airlock stops bubbling?
At this point in the process, you're pretty much committed to letting the ferment continue to completion. With fruit wine, the usual course of action is to add meta-bisulphite to the juice or pulp, and leave it for 24 hours before adding the yeast. The sulphite reduces the activity of wild yeasts and bacteria, giving the brewer's yeast a head start.
If the fruit is in good condition (i.e. no bruising or rot), some wine-makers will skip this step entirely. Pitching a lot of healthy, active yeast is usually sufficient.
Adding sulphite while fermentation is active will just reduce the activity of the brewer's yeast, which is not at all helpful.
According to this fellow's site, just throw the plums in a bucket and wait, agitate after a month to shake out the pits, wait a bit more, then run the plum wine through your still.
Don't use the sulphite if you want to distill because there is a chance to get bad smell into the distillate. If you want to protect your wine or beer from lactic bacterium you can use antibiotics: amoxicillin or doxycycline. Don't worry, it will not get into your distillate. The best defense from wild yeast is to make right start for your bread yeast. The best defense from acetic acid bacteria is to distill in time.