What is a Polyphosphate?

Phosphates are broken down into four primary groups. Orthophosphate is used for detergents and baking, pyrophosphate for water treatment and metal cleaning, and tripolyphosphate in meat processing and, oddly enough, dish detergent. The fourth group, and the focus of this article, is polyphosphate, which is commonly used in kaolin production, water treatment, food processing and preservation, and more.

How is Polyphosphate Manufactured?

Polyphosphate is a blend of phosphoric acid and other compounds or elements. Starting with phosphoric rock, there are two methods of processing phosphoric acid. The wet process combines the phosphoric acid with sulfuric acid. This compound is generally used in the agricultural market. The dry method uses heat to purify the phosphoric rock into phosphorous pentoxide. This phosphorous pentoxide is then dissolved in either water or phosphoric acid to increase its potency. The result is the basis for polyphosphate chemical compounds.

Polyphosphate in Water Purification

Polyphosphate is an effective agent that prevents the natural iron in well water from staining concrete and other porous surfaces brown. Anyone using well water can also appreciate its odor retardant ability. Orthophosphate and polyphosphate can be used together in treating water along with additional phosphate compounds. Their job is to stabilize the quality of water, inhibit corrosion of water pathways, remove scale deposits, and discourage unhealthy microbe growth.

Polyphosphate in Food Preparation

Interestingly, polyphosphate is often used in food preservation. Chickens are injected with a polyphosphate solution directly after slaughter. This process greatly reduces thaw drip, aids in water retention, and increases the stability of the cooked meat. This method is also used when freezing fresh fish. Although salt would accomplish the same result, it is not used because excess salt can create unpleasant tastes in preserved foods.

Polyphosphate and Your Health

Since most foods break down upon consumption into a simple phosphate in the human stomach, addition of polyphosphates to food or water poses little risk. While polyphosphates can be harmful if taken in very large quantities, most people usually do not exceed the recommended daily level in their diets so there is no cause for concern.