This document is applicable to pure cultures of STEC. The present standard describes the characterization of STEC strains, isolated from any source. In particular, the characterization of STEC strains described here regard: - subtyping of the Stx-coding genes; - determination of the presence of eae gene; - determination of the presence of aggR gene; - identification of the presence of genes associated to the following serogroups: O157, O26, O111, O103, O145, O121 and O45. The full characterization of the isolated STEC strains is achieved by performing all the modules described here. The characterization scheme is not sequential, and the different modules can be implemented separately based on specific needs (e.g. Regulatory needs, Competent Authority’s requests, clients’ request). Alternative methods may be used, including Whole Genome Sequencing (WGS), provided these are verified according to the reference standard ISO 16140-2.