A method for multiple and simultaneously detecting and quantifying of Listeria spp, Staphylococcus aureus, Campylobacter jejuni, and Escherichia coli 0157:H7, by extracting DNA from a sample; preparing a reaction mixture for enzymatic amplification of the extracted DNA and sets of pairs of oligonucleotide primers identified as SEQ ID No. 1 and SEQ ID No. 2, SEQ ID No. 4 and SEQ ID No. 5, SEQ ID No. 7 and SEQ ID No. 8, and SEQ ID No. 10 and SEQ ID No. 11, and probes with oligonucleotide sequences identified as SEQ ID No. 3, SEQ ID No. 6, SEQ ID No. 9 and SEQ ID No. 12; providing a thermostable DNA polymerase and magnesium salt to the reaction mixture; amplifying the reaction mixture by a PCR reaction; and determining the presence or absence, and quantification of the pathogens by using a fluorescent signal or fluorescence emission specific for each pathogen.