Arginine hydrochloride discs are used for Arginine hyrolysation test. To determine Arginine hydrolysation, the Arginine disc (DD050) is added in the Decarboxyalse Broth Base, Moeller (M393) which is used as a negative control for studying hydrolysation or as a base for the addition of amino acids. The test organism is inoculated into the broth containing the Arginine disc (DD050). The inoculated tubes are overlaid with sterile mineral oil and incubated at 35-37°C for up to 4 days. Positive Test: Colour of the medium changes from yellow to purple. Negative Test: Colour of the medium changes to yellow or there is no change