• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.79-86
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• 2002

Aflatoxin is a secondary fungal metabolite and is a public health hazard because it is a human carcinogenic and has many deleterious effects in men and animals. Rice is one of the better substrates far the fungus which can produce aflatoxins. This study was performed to investigate aflatoxin reduction during the cooking and processing of rice. Aflatoxin was produced by Aspergillus parasiticus ATCC 15517 on well-milled rice (Japonica type) at the level of 13.2 ppb. Cooked rice, rice cakes (baek-sol-gi, plain steamed rice bread), fermented rice (sikhye, sweet rice beverage), and popped rice were prepared from the aflatoxin-contaminated rice. Aflatoxin content in the samples was determined by high performance liquid chromatography. The total aflatoxin level was decreased to 46.9% in the cooked rice, 85.6% in the rice cakes, 11.4% in the fermented rice, and 7.6% in the popped rice, respectively (p.0.05). This reduction brought the level of aflatoxins down to below the Standard and Specification of korea (10 ppb), except for the rice cakes. These results indicate that washing, steaming, fermentation, and popping of rice was helpful in reducing the aflatoxin level in the rice and the most helpful factors were high temperature & high pressure. More research is needed to understand why the preparation of rice cakes did not reduce the level of aflatoxin as much as the other cooking methods.

• The Korean Journal of Mycology
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• v.20 no.3
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• pp.252-258
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• 1992

Thirty three species and two species varieties belonging to 14 genera of fungi were collected from 20 cowpea cultivars on glucose Czapek's agar (11 genera and 25 species+1 var.) and glucose-Czapek's agar supplemented with 10% NaCl (7 genera and 18 species+2 var.) at $28{\pm}2^{\circ}C$. The total count of fungi were 6716 colonies/g in all cowpea cultivars. On glucose-Czapek's agar and identified; Aspergillus flavus, A. niger, A. sydowii, A. flavus var. columnaris, A. terreus, Penicillium chrysogenum, Emericella nidutans and Rhizopus stolonifer. The total count of halotolerant or halophilic fungi was 3515 colonies/g on 10% NaCl-glueose-Czapek's agar and identified; the most common species were: A. flavus, A. sydowii, A. tamarii A. flavipes, A. niger, A. flavus var. columnaris, A. ochraceus, A. oryzae and P. chrvsogenusm. Thin layer chrormatographic analysis of chloroform extracts of the different seed samples revealed that four cultivars were naturally contaminated with aflatoxins $B_1,\;B_2,\;G_1$ and $G_2$, $(45-112\;{\mu}g/kg)$.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.25-28
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• 2007

A survey of total aflatoxin levels was conducted on 565 food samples (cereals, nuts, etc) collected in commercial markets. The determination of aflatoxins ($B_{1}$, $B_{2}$, $G_{1}$ and $G_{2}$) was performed using HPLC with fluorescence detector. The Limit of Detections (LODs) of the B group and G group were 0.05 ng/g and 0.07 ng/g, respectively. In addition, recoveries of rice, peanut butter, and red pepper flour were satisfactory. Total aflatoxin was detected 27 samples(4.8%) out of 565 samples. Incidence ratios in cereals, nuts, processed products, and other foods were 0.2, 0.4, 3.0 and 1.2%, respectively, but aflatoxin was not detected in pulse and dried fruits. The daily intake of total aflatoxin using food intakes was 0.04 ng/kg bw/day.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.57-66
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• 2017

Aflatoxins are classified as Group 1 (carcinogenic to humans) by the International Agency for Research on Cancer. In this study, a total of 134 fungal strains were isolated from 65 meju samples, and two fungal isolates were selected as potential aflatoxin $B_1$ ($AFB_1$)-biodetoxification fungi. These fungi were identified as Aspergillus oryzae MAO103 and A. oryzae MAO104 by sequencing the beta-tubulin gene. The two A. oryzae strains were able to degrade more than 90% of $AFB_1$ (initial concentration: $40{\mu}g/l$) in a culture broth in 14 days. The mutagenic effects of $AFB_1$ treated with A. oryzae MAO103 and MAO104 significantly decreased to 5.7% and 6.4%, respectively, in the frame-shift mutation of Ames tests using Salmonella typhimurium TA98. The base-substituting mutagenicity of $AFB_1$ was also decreased by the two fungi. Moreover, $AFB_1$ production by Aspergillus flavus was significantly decreased by the two A. oryzae strains on soybean-based agar plates. Our data suggest that the two $AFB_1$-detoxifying A. oryzae strains have potential application to control $AFB_1$ in foods and feeds.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.643-646
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• 2006

Because of potential health hazards of aflatoxins for humans, the present study was conducted to monitor aflatoxin $B_1\;(AFB_1)$ in livestock feeds. A total of 249 samples of feeds collected in Korea were analyzed by DC-ELISA for qualitative analysis of $AFB_1$. Then, 27 samples that were verified to contain $AFB_1$ by DC-ELISA were quantitated by HPLC/FLD. HPLC/FLD analysis revealed that only one sample collected from a farm contained 11 ppb of $AFB_1$, whereas the other samples collected from feed companies did not contain $AFB_1$. The presence of $AFB_1$ was further confirmed by LC/MS analysis. TLC analysis indicated that the result of the DC-ELISA was most likely due to possible contamination of other mycotoxins rather than $AFB_1$. In conclusion, HPLC/FLD analysis following DC-ELISA is necessary for rapid and accurate detection of $AFB_1$.

• Korean Journal of Microbiology
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• v.24 no.4
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• pp.352-356
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• 1986

A study was carried out to determine the effect of ginseng saponin an its related materials on aflatoxin production by Aspergillus parasiticus NRRL2999 in glucose-salts(GS) medium. Maximal growth of the mold and AF froduction in the medium occurred after 5 and 9 days at $28^{\circ}C$, respectively. When various concentrations of saponin added to the medium aflatoxin synthesis were significantly reduced (p<0.05) compared to the control after 9 days at $28^{\circ}C$. 0.05% of saponin inhibited aflatoxin production most effectively in the low concerntrations of saponin (0.01-0.2%) and the toxin synthesis reduced with an increasing concentrations of saponin in the high concentrations (0.03-5.0%). Various concentrations (0.01-1.0%) of saponin diol and triol in the media also caused to reduce aflatoxin synthesis by the mold (p<0.05). All saponin fractions were found to decrease aflatoxin production significantly. Saponin fraction numbers of 1,2,4 and 6 were shown to reduce aflatoxin production effectively, and the number 1 was the most effective. Addition of 0.05% of nucleic acid related materials to the medium reduced aflatoxin production (p<0.05). Aflatoxins could not be found in broth at all, but in mycelia when 0.05% of caffeine was added to the medium. Aflatoxin synthesis was well correlated with total lipid synthesis, growth and glucose uptake. When aflatoxin synthesis inhibited (5.0% of saponin) both total lipid synthesis and growth were stimulated and the efficiency of glucose utilization was reduced.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.187-192
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• 2017

The consumption of herbal medicines has been increasing with growing interest in health. However, due to recent climate change and the complex distribution process of herbal medicines with high import dependence the likelihood of contamination with mycotoxin has been increased. Mycotoxins are emerging as key indicators for ensuring safety of herbal medicines. A total of 498 herbal medicine samples were screened for mycotoxin contamination in this study. Aflatoxin in the herbal medicine samples was extracted by using immunoaffinity column, then the extracted aflatoxin was quantified via high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method. The extraction method was verified by linearity, recovery, LOD and LOQ. Aflatoxins were detected in 39/498 samples in an average of $7.670{\mu}g/kg$ ($0.610-77.452{\mu}g/kg$ range). Although safety standards for Corydalis Tuber is not currently available in korea, five of the 39 samples had high concentration of aflatoxins (average of $14.9{\pm}4.1{\mu}g/kg$). In conclusion, it is urgent to establish safety criteria of aflatoxin in Corydalis Tuber. The results of the current study suggest that continuous monitoring is necessary for proactive management of herbal medicine safety.