Lactose is a sugar commonly found in milk and dairy products. It is used in smoke compositions and also used as a binder to hold together the chemical compounds that create the sparkly effect.
Lactose powder is typically extracted from whey, which is the liquid that remains after milk has been curdled and strained during cheese production. The basic steps involved in the extraction process are separation which is when the whey is separated from the curds using a centrifuge, which spins the mixture at high speeds to separate the denser curds from the liquid whey. Next is clarification, which is when the whey is then clarified to remove any remaining solids or impurities. This is typically done by filtering the liquid through a series of screens and membranes. Next is concentration when the whey is then concentrated using a process called evaporation. This involves heating the whey in large evaporators to remove much of the water, leaving behind a thick liquid. Finally, crystallization is when the concentrated whey is then cooled and allowed to crystallize. The lactose crystals are separated from the remaining liquid using a centrifuge, and then washed and dried to remove any remaining moisture.
Lactose is not particularly toxic or dangerous.