this is astounding.
throw this shit out.
Pure LA can be obtained by conversion of calcium lactate to zinc lactate using sulphate or zinc carbonate, and zinc lactate is recrystallized and dissolved in water. Subsequently, zinc is precipitated as zinc sulfide using a solution of hydrogen sulfide (Trindade 2002). LA solution is clarified with coal, filtered, and vacuum evaporated. Zinc salt is the most suitable for this operation because it crystallizes better than any other lactate (Pereira 1991).
so, the zinc separates from the lactic acid when dissolved in water - and is chosen because it dissolves the most easily. the industrial process then needs to remove the zinc to get pure lactic acid, but that's not important in the context of putting the stuff in your mouth.
crest is trying to ruin your teeth.
and, this is the product with the "dentists recommend" seal on it.
remarkable.
and, people wonder why there's so much skepticism about dentistry out there....