In dairy applications, phosphates are used for a number of functions. Phosphates stabilize milk proteins against coagulation from extreme heat, pH or sheer; buffer products within the desired pH range; support emulsification by interacting with proteins; and bind calcium in milk gels. Nutritionally, phosphates can help fortify with calcium, magnesium or potassium. Phosphates sequester metal ions and also have bacteriostatic effects. Many of the applications in processing of dairy products involve interactions between phosphates and casein, or the calcium in the casein micelles.

Phosphates start with phosphoric acid; when combined with alkali metals, such as sodium, potassium, calcium or magnesium, an ortho-phosphate salt will form.  Upon  heating, ortho-phosphates combine  to form chains, first pyro-2, then tripoly -3, and then longer chains known as polyphosphates or hexametaphosphate–with a chain length from 4 - 28 or greater.