Citric acid is a natural preservative found in citrus fruits such as lemons and limes.
It is helpful with inhibiting the growth of mold and bacterial growth, especially with sprouting because of the high temperatures in the jar. To reduce spoilage in sprouting, add 1 tsp. per quart to soak and rinse water.
Citric Acid is also useful in canning, drying or freezing foods. It can be used to preserve Vitamin C content, retard spoilage and prevent discoloration. Use 1 tsp. per quart of water or juice for most fruits and vegetables.