This method is for the detection and enumeration of Salmonella (CAS registry number 68583-35- 7) in treated biosolids by enrichment, selection, and characterization. It is intended to enumerate Salmonella to help determine the suitability of biosolids for land application in compliance with 40 Code of Federal Regulations (CFR) Part 503. Although Method 1682 is similar to existing recognized procedures using separate media for enrichment, selection, and confirmation of the organism, it is intended to be more specific and have greater recovery. This method is designed to meet monitoring requirements for Salmonella under 40 CFR Part 503 Subpart D. Subpart D of the Part 503 regulation defines the requirements for biosolids to be classified as either Class A or B with respect to pathogens. Classification of biosolids prior to land application provides a means to protect public health and the environment. Following appropriate treatment, a biosolid sample is classified as Class A if Salmonella densities are below 3 MPN / 4 grams of total solids (dry weight basis). Although the Part 503 regulation does not specify the total number of samples for Class A biosolids, it suggests that a sampling event extend over two weeks, and that at least seven samples be tested to confirm that the mean bacterial density of the samples is below 3 MPN / 4 g of total solids (dry weight basis). The analysis of seven samples increases the method precision by reducing the standard error caused by inherent variations in biosolid quality. Although Method 1682 is selective for Salmonella bacteria, it does not differentiate among Salmonella species. Method 1682 was submitted to interlaboratory validation in Class A biosolid matrices. A comprehensive evaluation of the study results is presented in the validation study report. Based on these validation study results, Method 1682 is approved for the analysis of Salmonella in Class A biosolid matrices. This method is not intended for use in water samples or as a test for microorganisms other than Salmonella. Use of this method and appropriate validation for matrices other than Class A biosolids is the responsibility of the user. Any modification of the method beyond those expressly permitted is subject to the application and approval of alternative test procedures under 40 CFR Parts 136.4 and 136.5.