A lum is used as an ingredient in baking powder and is used to give crispness to pickles and maraschino cherries and to harden gelatin. Alum can be a dangerous substance when not used properly. Alum is legal to use in baking powders. In pickles and cherries, the amount usually left in the packaged product amounts to less than 0.2 percent.
Research shows that it has no effect until after the pickles have been fermented.
Then it is used only in a soak solution. It should be washed off thoroughly before completing the recipe. Do NOT put alum in the final pickling liquid. Douche alum is not food grade. User support of VU is appreciated.