Abstract: A method for detecting the presence or absence of pathogenic. STEC in food samples includes incubating the food sample in a culture medium to obtain an E. coli stock medium; lysing the E. coli to obtain a E. coli DNA; and subjecting the DNA to PCR, and amplifying the following genes or fragments thereof: stx1 and/or stx2 encoding Shiga toxin 1 and Shiga toxin 2, 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, if stx1 and/or stx2 and the eae gene and the specific biomarker gene for at least one serogroup are amplified in the PCRs: verifying the presence of the one or more specific serogroups of STEC by PCRs on concentrates of the E. coil stock medium.