Simultaneous detection of three foodborne pathogenic bacteria in food samples by microchip capillary electrophoresis in combination with polymerase chain reaction

A rapid and sensitive PCR based strategy in combination with microchip capillary electrophoresis (MCE) was employed to simultaneously detect three foodborne pathogenic bacteria. Three pairs of primers were specially designed for the amplification of target genes from Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella enterica serovar Typhimurium (S. Typhimurium). The PCR products along with standard DNA fragments were employed to optimize the separation conditions in MCE. Under optimal conditions, detectable separation of the PCR products (1.6–3.5 ng μL⁻¹) from the three foodborne pathogenic bacteria was achieved within 135 s. The limits of detection of the three bacteria were concluded to be as low as 45 CFU mL⁻¹ for E. coli, 62 CFU mL⁻¹ for S. aureus and 42 CFU mL⁻¹ for S. Typhimurium. The RSD of migration time was in the range of 0.5–0.8%. We conclude that MCE along with PCR holds real potential for rapid analysis and detection of nucleic acids from routine foodborne pathogenic bacteria.