Disodium phosphate is used primarily as a food additive for stabilization, emulsification and phosphate fortification. It can also be used for industrial purposes as a corrosion inhibitor, as a pesticide ingredient and in industrial and other cleaning products. Although it's safe in the form in which it's added to food products, disodium phosphate in its pure form can sometimes be toxic on contact or if ingested.
Identification
Disodium phosphate's chemical formula is Na2HPO4, meaning that for every one molecule of disodium phosphate, there are two sodium atoms, one hydrogen atom, one phosphate atom and four oxygen atoms. It's a white, odorless crystal that's soluble in water and stable under normal storage conditions. It is not flammable.
Use as a Buffer
Disodium phosphate is an acid salt. Acid salts serve as buffers, controlling the acidity or alkalinity of an environment. In a buffer system, the pH of the solution changes little upon the addition of a small amount of strong acid or base. In this capacity, acid salts act both as an acid or a base, depending upon the other chemicals in the environment.
Food Preservative Use
Disodium phosphate prevents or slows down the growth of bacteria and other microorganisms on foods. It also acts as a protein coagulate, helping form semi-soft foods such as pudding, and an emulsifier, helping compounds mix. In addition, it provides phosphate fortification and decreases the cooking time of products such as pastas and hot cereals.
Industrial Use
Disodium phosphate is in various industrial cleaning products, working as a disinfectant, fungicide and sanitizer. It is also used as a corrosion inhibitor in industrial cooling systems, as a water softening agent, as flame retardant for wood and as an ingredient in waterproofing agents. It can also be used in medications designed to eliminate retained fluid.
Toxicity
Inhalation of disodium phosphate could irritate the respiratory tract, causing shortness of breath and coughing. Because phosphates are slowly and incompletely absorbed, ingestion seldom results in negative systemic effects. But on rare occasions, ingestion of the pure chemical could lead to vomiting, diarrhea and lethargy. Because disodium phosphate acts as either an acid or base, disturbances in the buffer system of the blood may also occur. Upon direct contact with skin or eyes, disodium phosphate may induce redness, pain or allergic reaction.
Member Comments
verystressed June 4
Extremely informative. Thank you Dr. Wasserman
Underuberdog July 10
I became violently ill after eating a large serving of an under-cooked cereal product containing Disodium Phosphate. Within one hour I experienced severe vomiting lasting a brief two minutes, then diarrhea that lasted a hellish twenty four hours. My fasting blood glucose levels rocketed to 200, twice their normal range, even with consistent doses of water to remain hydrated.
I hope you could comment on the chemical changes that occur with DSP as it is "cooked" or "raw" when ingested. I suspect that I could have cooked the cereal longer and avoided the ensuing misery. Is there any scientific basis for this hypothesis?