What it is
E542, also called edible bone phosphate, is an anti-caking and texturising agent produced from defatted and steam-treated animal bones (typically cattle).
Why it matters
Used as a free-flow agent in seasoning blends, dried soups, gravy granules, baby formula, and toothpaste. The name "bone phosphate" makes the source obvious — but on some labels it appears only as the E-number.
What to do
Always not vegan. Look for plant-based alternatives such as silicon dioxide (E551) or magnesium carbonate (E504) in similar product categories.