This method describes multiple-tube fermentation procedures (also called the most probable number (MPN) procedure) for the detection and enumeration of fecal coliform bacteria in biosolids. These methods use culture-specific media and elevated temperature to isolate and enumerate fecal coliform organisms. Fecal coliform bacteria, including Escherichia coli (E. coli), are commonly found in the feces of humans and other warm-blooded animals, and indicate the potential presence of other bacterial and viral pathogens. This method is adapted from method 9221E in Standard Methods for the Examination of Water and Wastewater, 20th Edition, for the determination of fecal coliform bacteria in a variety of matrices (Reference 19.1). This method is designed to meet the survey and monitoring requirements of U.S. Environmental Protection Agency (EPA) in regulating the use and disposal of biosolids under 40 CFR Part 503. Subpart D of the 503 regulations protects public health and the environment through requirements designed to reduce the potential for contact with disease-bearing microorganisms (pathogens) in biosolids applied to land or placed on a surface disposal site. Fecal coliform density is expected to correlate with the probability of pathogens present and document process performance (vector attraction reduction).