A-1 Medium (Broth), double strength (2x A-1), is a selective broth used for isolation and presumptive identification of fecal coliforms in water. Andrews and Presnell developed A-1 Medium in 1972 to recover Escherichia coli from estuarine water in 24 hours instead of 72 hours, and in greater numbers without pre-enrichment. A-1 Medium can be used in a single step procedure for the detection of fecal coliforms in source water, seawater, treated wastewater, and foods.• Product meets APHA, BAM, EPA, NF, and SMWW reference methods and performance criteria.• A-1 Medium should be used by trained professionals within a laboratory setting. • Product is not intended for use in the diagnosis or treatment of disease or other human conditions.• Double Strength (2x)