A1 broth (original) (raw)

An A1 broth is a liquid culture medium used in microbiology for the detection of fecal coliforms in foods, treated wastewater and seawater bays using the most probable number (MPN) method. It is prepared according to the formulation of Andrews and Presnell given below. It is used with a Durham tube, a positive tube being one that exhibits a trapped bubble of gas.