Detection of aflatoxin-producing molds in Korean fermented foods and grains by multiplex PCR.
An assay based on multiplex PCR was applied for the detection of potential aflatoxin-producing molds in Korean fermented foods and grains. Three genes, avfA, omtA, and ver-1, coding for key enzymes in aflatoxin biosynthesis, were used as aflatoxin-detecting target genes in multiplex PCR. DNA extracted from Aspergillus flavus, Aspergillus parasiticus, Aspergillus oryzae, Aspergillus niger, Aspergillus terreus, Penicillium expansum, and Fusarium verticillioides was used as PCR template to test specificity of the multiplex PCR assay. Positive results were achieved only with DNA that was extracted from the aflatoxigenic molds A. flavus and A. parasiticus in all three primer pairs. This result was supported by aflatoxin detection with direct competitive enzyme-linked immunosorbent assay (DC-ELISA). The PCR assay required just a few hours, enabling rapid and simultaneous detection of many samples at a low cost. A total of 22 Meju samples, 24 Doenjang samples, and 10 barley samples commercially obtained in Korea were analyzed. The DC-ELISA assay for aflatoxin detection gave negative results for all samples, whereas the PCR-based method gave positive results for 1 of 22 Meju samples and 2 of 10 barley samples. After incubation of the positive samples with malt extract agar, DC-ELISA also gave positive results for aflatoxin detection. All Doenjang samples were negative by multiplex PCR and DC-ELISA assay, suggesting that aflatoxin contamination and the presence of aflatoxin-producing molds in Doenjang are probably low.
Yang
Zheng-You
ZY
Division of Applied Life Science of Graduate School, Gyeongsang National University, Chinju 660-701 Korea.
Shim
Won-Bo
WB
Kim
Ji-Hun
JH
Park
Seon-Ja
SJ
Kang
Sung-Jo
SJ
Nam
Baik-Sang
BS
Chung
Duck-Hwa
DH
D000348:Aflatoxins / Q000302:isolation & purification*; D017931:DNA Primers; D004271:DNA, Fungal / Q000032:analysis*; D002523:Edible Grain / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005285:Fermentation; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
D000348:Aflatoxins; D017931:DNA Primers; D004271:DNA, Fungal