CALCIUM carbonate is another non-food ingredient commonly found in processed baby foods (eg: in rusks, rice with milk, beef with vegetables and mixed fruits).
It is actually another name for pure chalk.
Calcium carbonate is useful to manufacturers as it helps mixtures run smoothly, and not develop lumps or cakes. It can also be used as a colouring agent, making food appear whiter.
Calcium carbonate is banned in several countries, including Canada and Sweden.
High levels of chalk (calcium carbonate) in the diet may lead to constipation. And excessive absorption of calcium can give rise to a disorder called hypercalcaemia, which can lead to calcium being deposited in the kidneys, heart and other organs.
Chalk in baby foods is unnecessary because both breast milk (and infant formula) have plenty of calcium.
Besides calcium carbonate, you should also look out for dicalcium phosphate — this is another form of calcium which is sometimes also used in baby foods.