Lactic acid is a organic acid that is white in a solid state and is miscible with water to become a clear liquid. It can be derived naturally or through artificial synthesis. 

Lactic acid is naturally produced through bacterial fermentation of milk products, or synthetically through chemical synthesis of acetaldehyde.  

It is approved as a food additive carrying the E number E270. Main applications include sour milk products, yogurts, cottage cheeses, sour beers, and as a decontaminant during meat processing.