An evaluation of aflatoxin and cyclopiazonic acid production in Aspergillus oryzae.
To date, edible fungi such as Aspergillus flavus var. oryzae (A. oryzae) has been considered as safe. However, some strains can produce mycotoxins. Thus, the biosynthetic ability to produce mycotoxins should be reevaluated to determine the safety of edible fungi. We analyzed the production of aflatoxins and cyclopiazonic acid (CPA) from edible fungi such as A. oryzae isolated from various Korean foods using multiplex PCR, enzyme-linked immunosorbent assay, and high-performance liquid chromatography (HPLC). In the multiplex PCR analysis of aflatoxin biosynthetic genes omtB, aflR, ver-1, and omtA, 5 of 19 Aspergillus strains produced all PCR products. Among them, aflatoxin B1 and aflatoxin B2 were detected from only A. flavus KACC 41403 by HPLC. Aflatoxins were not detected from the other four strains that produced all positive PCR bands. Aflatoxin also was not detected from 12 strains that had PCR patterns without aflR or ver-1 and from 2 strains that did not produce any of the expected PCR products. Only the seven A. oryzae strains that produced all of the positive PCR bands including the CPA biosynthetic genes maoA, dmaT, and pks-nrps produced CPA. CPA and aflatoxin production must be evaluated before A. oryzae strains are used for the development of fermented foods.
Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 152-742, Republic of Korea.
Nam Yeun
NY
Kim
Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seongbuk-gu, Seoul 136-702, Republic of Korea.
Jin Hee
JH
Lee
Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seongbuk-gu, Seoul 136-702, Republic of Korea.
Inhyung
I
Lee
Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 152-742, Republic of Korea, Research Institute; Bifido, Inc., Gangwon-do, Seoul 250-804, Republic of Korea. geji@snu.ac.kr.
Geun Eog
GE
Ji
D000348:Aflatoxins / Q000096:biosynthesis*; D001236:Aspergillus oryzae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005516:Food Microbiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D007211:Indoles / Q000378:metabolism*
D000348:Aflatoxins; D005656:Fungal Proteins; D007211:Indoles; C000543:cyclopiazonic acid