Sodium bisulfite (or sodium bisulfite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO₃. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. It is a white solid with an odor of sulfur dioxide. Regardless of its ill-defined nature, “sodium bisulfite” is a food additive with E number E222.

Sodium citrates are used as acidity regulators in food and drinks, and also as emulsifiers for oils. They enable cheeses to melt without becoming greasy. It reduces the acidity of food as well. Sodium citrate is used to prevent donated blood from clotting in storage. It is also used in a laboratory, before an operation, to determine whether a person’s blood is too thick and might cause a blood clot, or if the blood is too thin to safely operate. Sodium citrate is used in medical contexts as an alkalinizing agent in place of sodium bicarbonate,^[1] to neutralize excess acid in the blood and urine.^[2] It has applications for the treatment of metabolic acidosis^[3] and chronic kidney disease.