A selective medium for the enrichment of Enterobacteriaceae and the detection of Escherichia coli in pharmaceutical products. The inclusion of bromocresol purple indicator makes the colour change caused by acid production from the fermentation of lactose easy to read with gas formation. The presence of ox bile helps to suppress the growth of Gram-positive and non-enteric bacterial species. This formulation complies with the Harmonized USP/EP/JP.

Nitrogen is supplied by the gelatin peptone whilst lactose serves as the fermentable carbohydrate source. Ox bile is the selective agent helping to suppress Gram-positive organisms and bromocresol purple detects the pH change as a result of the fermentation of lactose.

Preparation

Suspend 35.0g of the medium in 1L of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Dispense into suitable containers with Durham tubes added. Sterilise at 121°C for 15 minutes.