Inositol Discs are used to differentiate bacteria based on the inositol fermentation ability. Microorganisms can only ferment certain molecules, depending on the enzymes they possess to break down molecules. Fermentation can be detected by gas production (CO₂) in liquid media and/or color change of pH caused by acid production. The inositol discs are aseptically added to any sugar-free basal media to test the ability of the organism to hydrolyze inositol, a carbocyclic sugar, as the sole source of carbon and energy during fermentation. Inositol is typically fermented under acid and gas production by many Enterobacter bacteria.

Inositol Discs are recommended to detect inositol fermenting bacteria in food and environmental samples. They find their application in various sectors such as the food and dairy industry, water industry, pharmaceutical laboratory testing, cosmetic industry, environmental and sanitary testing, clinical diagnostic, etc.