What it is and where it comes from
Lactic acid is made by bacteria that ferment sugar or starch from corn, beet or cane. Its salts (E325 to E327) are made from it. No animal or alcohol is involved.
Where you find it
Sauces, pickles, olives, sweets, bread, drinks and processed meat.
What to look for on the label
Nothing to check for halal. It is also fine for people who avoid dairy.
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.