Coliforms are all facultative and aerobic rod-shaped, gram-negative, non-spore-forming bacteria that produce lactose by fermentation with gas and acid production within 48 hours, at temperatures of 35 degrees Celsius. Methods to identify, enumerate and presumedly identify coliforms are utilized in the testing of dairy and food products. One method of performing the presumptive test to identify coliforms employs the Violet Red Bile Agar (VRBA). The Violet Red Bile Aggar (VRBA) is an selec-tive medium that can be used to detect and quantify lactose-fermenting coliform microorganisms.