What it is and where it comes from
E170 is a natural mineral, mined as limestone or chalk, or made from it. It is used as a white colour, to add calcium, and to balance acidity.
Where you find it
Flour and bread, plant milks, sweets, chewing gum, tablets and calcium supplements.
What to look for on the label
Nothing to check for halal.
This is a guide, not a fatwa. Recipes change, so check the label, look for halal certification, and ask your local imam where scholars differ.