Para Hydroxybenzoate esters and their sodium salts, usually named parabens, have been used for many decades as antimicrobial preservatives in cosmetics, food products and pharmaceutical formulations. Parabens are effective over a wide pH range with a broad spectrum of antimicrobial activity, and are also effective against yeasts and moulds. Antimicrobial activity increases with increasing alkyl chain length for the commonly used methyl, ethyl, propyl, and butyl parabens.