Origin
Calcium carbonate - also known as calcite - is the calcium salt of carbonic acid and is a colorless, odorless solid that is very poorly soluble. Calcium carbonate occurs very frequently in rocks but also in the shells of mollusks, snails, and crustaceans. For use as a food additive, E 170 is either obtained from finely ground limestone or synthesized through a chemical reaction between calcium ions and carbonates.
Usage
There are no restrictions on the use of E 170. It is often added to foods such as grape juice, baking products, baby food, coatings for pills and candies, cheese, and chewing gum.
Risks
To date, there have been no findings that calcium carbonate as a food additive poses any risks. E 170 is considered completely harmless. It is also used to color medicines and pharmaceuticals.