Gelatin is used in preparing microbiological culture media. In addition to providing nutrients for bacterial growth, gelatin allows for the determination of gelatin-liquefying microorganisms and the enumeration of proteolytic organisms in water samples. Although gelatin was the first gelifying agent employed in culture media, its main disadvantages for this purpose include its melting over 20 ºC (a temperature below the optimum for most bacteria) and the fact that microorganisms with the enzyme gelatinase can liquefy it.