E542 is the food additive number for bone phosphate which is produced from grinding animal bones. It is used in cosmetics including toothpaste. It is used as an anti-caking agent, an emulsifier, and as a source of phosphorous in dietary supplements. It is often made from pig bones and is not suitable for vegans, vegetarians, and those adhering to a kosher or halal diet. When you see an “E-number” like E542, it refers to an ingredient that has been approved by the European Union for use as a food additive.