A method for determining the presence or absence of one or more specific serogroups of pathogenic Shiga toxin-producing E. coli (STEC) in a food sample, comprising - incubating the food sample in a culture medium enabling growth of E. coli to obtain an E. coli stock medium; - performing a lysis of the E. coli in the stock medium to obtain a sample solution comprising E. coli DNA; and - subjecting the sample solution to a first series of polymerase chain reactions, using primers to amplify the following E. coli genes or fragments thereof: • stx1 and/or stx2 encoding Shiga toxin 1 and Shiga toxin 2, respectively, • for each STEC serogroup to be determined, the subtype of the eae gene of that serogroup encoding an intimin, and • for each STEC serogroup to be determined, a biomarker gene specific for that serogroup; and, in case that stx1 and/or stx2 as well as the eae gene and the specific biomarker gene for at least one serogroup are amplified in the first series of PCRs: - verifying the presence of the one or more specific serogroups of STEC by performing a second series of PCRs on concentrates of the E. coli stock medium and, optionally, a third series of PCRs on single E. coli colonies derived from the concentrates, wherein the verification of the presence of the one or more specific serogroups of STEC comprises - performing an immunoconcentration of the E. coli stock medium for each serogroup, using antibodies directed against the STEC of the respective serogroup; - isolating DNA from the immunoconcentrates; and - subjecting the DNA to the second series of PCRs, using primers to amplify the following E. coli genes or fragments thereof: • stx1 and/or stx2, • the subtypes of the eae gene of the respective serogroups, and • optionally, the biomarker genes specific for the respective serogroups. - incubating the food sample in a culture medium enabling growth of E. coli to obtain an E. coli stock medium; - performing a lysis of the E. coli in the stock medium to obtain a sample solution comprising E. coli DNA; and - subjecting the sample solution to a first series of polymerase chain reactions, using primers to amplify the following E. coli genes or fragments thereof: • stx1 and/or stx2 encoding Shiga toxin 1 and Shiga toxin 2, respectively, • for each STEC serogroup to be determined, the subtype of the eae gene of that serogroup encoding an intimin, and • for each STEC serogroup to be determined, a biomarker gene specific for that serogroup; • stx1 and/or stx2 encoding Shiga toxin 1 and Shiga toxin 2, respectively, • for each STEC serogroup to be determined, the subtype of the eae gene of that serogroup encoding an intimin, and • for each STEC serogroup to be determined, a biomarker gene specific for that serogroup; - verifying the presence of the one or more specific serogroups of STEC by performing a second series of PCRs on concentrates of the E. coli stock medium and, optionally, a third series of PCRs on single E. coli colonies derived from the concentrates, - performing an immunoconcentration of the E. coli stock medium for each serogroup, using antibodies directed against the STEC of the respective serogroup; - isolating DNA from the immunoconcentrates; and - subjecting the DNA to the second series of PCRs, using primers to amplify the following E. coli genes or fragments thereof: • stx1 and/or stx2, • the subtypes of the eae gene of the respective serogroups, and • optionally, the biomarker genes specific for the respective serogroups. • stx1 and/or stx2, • the subtypes of the eae gene of the respective serogroups, and • optionally, the biomarker genes specific for the respective serogroups.