Himedia A-1 Broth

A-1 Broth is recommended for detecting faecal coliforms in water samples waste water, seawater and food by MPN Method. Andrews and Presnell devised A-1 Medium, which was capable of recovering Escherichia coli from estuarine waters in 24 hours instead of 72 hours by avoiding the pre-enrichment step as recommended by APHA. This greatly reduced the time required for the complete identification of E. coli by the elevated temperature and most probable number (MPN) methods, routinely used for water analysis. It substantially reduces the incidence of false positive cultures. The results obtained by using 3-hours pre-incubation step (using A-1 Medium) were statistically comparable with the two-step MPN technique for the enumeration of E. coli in chlorinated waste-water.