Establishment of a PCR method with an internal amplication control for detection of Cronobacter sakazakii in foods

The traditional detection method of Cronobacter sakazakii was time- consuming,operation- complicated,low sensitivity and was often influenced by the environmental factors,and the physical and chemical properties of food,which might lead to false negative results. In this study,we used 16 S rRNA gene as an internal amplification control,designed primers targeting grx B of C. sakazakii,optimized the reaction conditions and finally,established a PCR method with an internal amplication control for C.sakazakii detection.The results of detection of 20 strains including Cronobacter and non- Cronobacter by this method showed that these primers were specific for C. sakazakii detection. The sensitivity of established detection assay for C.sakazakii purified genomic DNA and pure cultures were 2.15 × 102 fg / μL and 9.4 × 103 CFU / m L,respectively. The detection for artificially contaminated infant milk powder showed that C.sakazakii could be detected after 8 h enrichment culture when the C.sakazakii inoculation was 0.94 CFU / g. This detection method demonstrated a good specificity and sensitivity,and could eliminate false- negative results caused by inhibitor of DNA polymerase in the PCR reaction reagents,and suitable for rapid detection of foodborne C.sakazakii.