Optimization of rapid detection of Escherichia coli O157:H7 and Listeria monocytogenes by PCR and application to field test.
For rapid detection of Escherichia coli O157:H7 and Listeria monocytogenes, simple methods for sample preparation and PCR were established and applied to a field test. To improve specificity, primer sets LP43-LP44 and C(+)-D(-) were selected for E. coli O157:H7 and L. monocytogenes, respectively. Through centrifugation and partial heat treatment after enrichment, E. coli O157:H7 and L. monocytogenes were detected at 1 initial CFU without genomic DNA extraction in the culture and with artificially inoculated food samples including milk, chicken, ham, and pork. Based on the optimized PCR method, a feasibility test was carried out using randomly collected field samples. To remove false positives and false negatives, a PCR method using several primer sets, including the optimized primer set, and a standard culture method were used. With the PCR detection and standard culture methods, two pork samples were positive for L. monocytogenes after enrichment, indications that the PCR assay could be effectively used for rapid, sensitive, and species-specific detection of foodborne pathogens.
Food Safety Team, Korea Food Research Institute, Seongnam, Kyunggi 463-746, Republic of Korea.
Gi-Seong
GS
Moon
Wang June
WJ
Kim
Weon-Sun
WS
Shin
D001483:Base Sequence; D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis*; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013045:Species Specificity
D017931:DNA Primers; D004269:DNA, Bacterial