Potassium MetaBisulfite (KMBS) powder aka campden is ideal for killing mold off fruits, stabilizing your brew, making dessert beverages, and in general disinfecting your apparatus, equipment and instruments. Please use it along with your pH scale and ppm charts of sulfites to use the correct amount.
This packet contains 25gm of powder which is equivalent to 50 tablets. So, use sparingly. This is equivalent to tablets and can be used in the same ratio (but much cheaper). It is also used as a sanitizer.
One teaspoon (US dry measure) of potassium metabisulphite weighs approximately 1.4 grams. So, 0.44 grams (the contents of one Campden tablet) is0.44/1.4 = 0.314, or roughly 1/3 of a teaspoon.