Where can you buy nabitor a natural mold inhibitor?

Try vinegar, raisin juice concentrate, Prune Juice concentrate or plum paste if these will work with the recipe you're using. google the last three to find sources for the last three on the internet; of course, you can buy vinegar at any grocery store.

Good sanitation also helps. Clean everything, and make sure that there are no mold infestations anywhere in the building where you are cooking. A small concentration of mold in another part of the building, even if it's in a different room on a different floor, can be enough to cause problems as the spores spread far, wide and quickly. If you are having problems with mold in your refrigerator, clean it thoroughly and wipe all interior surfaces down with a vinegar solution and a clean cloth.