Millipore 00563-500G-F MM ChromoSelect Agar Powder

Features:

• Application: MM ChromoSelect Agar is recommended for the identification and differentiation of Salmonella and non-salmonella like Citrobacter from water samples.
• Preparation Note: Suspend 49.13 g in 1000 ml distilled water. Heat to boiling to dissolve the medium completely. DO NOT AUTOCLAVE OR OVERHEAT. Cool to 45-50°C and pour into sterile petri plates.

MM ChromoSelect Agar was formulated by Miller and Mallison (1) for specific isolation and detection of Salmonellae. This medium is superior to XLT4 Agar in supporting Salmonella growth due to the appropriate proportion of four sugars. Most differential and selective media are formulated with one or more sugars and pH indicators respectively. The utilization of sugars by organisms results in pH-changes. This is used as a means of distinguishing Salmonella from competing bacteria based on colony color. Salmonella usually are unable to ferment these sugars (2) which support the growth of competing bacteria. Thus, other bacteria tend to overgrow Salmonellae, masking their presence. The inclusion of sugars like Mannitol, Cellobiose and Trehalose stimulate the better initial growth of Salmonella cells. However, the low concentrations of these sugars do not interfere with the utilization of protein and H2S production. Presence of lactose suppresses H2S production by nonsalmonellae like Citrobacter freundii. A chromogenic mixture, present in this medium helps to differentiate between lactose fermenters and nonfermenters. Lactose fermenters give bluish-green colored colonies which would have been impossible to differentiate with an indicator based on pH change. Inclusion of tergitol 4 in the medium suppresses the presence of Proteus and Providencia colonies. Peptone (vegetable) and Vegetable Extract provide essential nitrogen compounds.