• Microbiology and Biotechnology Letters
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• v.8 no.4
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• pp.237-245
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• 1980

Microorganisms growing on Dried-Persimmon have heed isolated ana identified. Fluorescent substance were extracted from a putrefactive Dried-Persimmon after invaded Toxigenic Fungi, and compared with Aflatoxin by Thin layer chromatography and u. v. absorption spectra. The results obtained were summarized as follows: 1) Fungal invasion was frequently appeared at the beginning of storage, and after then Bacteria invasion was followed. 2) Several Genera of microorganisms (Aspergillus sp., Escherichia sp., Mucor sp., Alternaria sp., Penicillium sp. ) were observed in Dried-persimmon during storage. Aspergillus sp., one of all Genus was predominant. 3) Two strains (Aspergillus flavus Group, Penicillium citrimum Series) of 6 Fungi had Fluorescent substance, which was presumed Aflatoxin-like substance. 4) The Rf value of T. L. C. ana λ max of u. v. absorption spectra showed the same value as the standard of Aflatoxin. It is suppose that the Fluorescent substance in Dried-Persimmon is a Aflatoxin-like substance.

• Food Science and Preservation
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• v.30 no.1
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• pp.28-41
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• 2023

Non-aflatoxigenic Aspergillus oryzae and aflatoxigenic A. flavus cannot be clearly identified by partial sequencing of the internal transcribed spacer (ITS) and 18S ribosomal ribonucleic acid (18S rRNA) regions. This study aimed to compare the accuracy among three aflatoxin detection methods using ultra-performance liquid chromatography (UPLC), high-performance liquid chromatography (HPLC), and an enzyme-linked immunosorbent assay (ELISA) kit and to select the non-aflatoxigenic Aspergillus sp. isolated from soybean paste. All analytical methods were suitable according to the international standards of Codex Alimentarius FAO-WHO (CODEX) or the Ministry of Food and Drug Safety (MFDS). UPLC exhibited the best of limit of detection (LOD) and limit of quantification (LOQ). Based on UPLC, HPLC, and the ELISA kit assay, the P5 and P7 strains isolated from soybean paste had 1,663.49, 1,468.12, and >20 ㎍/kg and 1,470.08, 1,056.73, and >20 ㎍/kg, respectively, detected and re-identified as A. flavus. In contrast, the P3 and P4 strains (A. oryzae), which were detected below the MFDS standards in all assays, were confirmed as non-aflatoxigenic fungi. Among the methods evaluated for quantitative analysis of aflatoxin, UPLC and HPLC are superior in terms of accuracy, and the ELISA kit rapidly detects low concentrations of aflatoxin. Furthermore, this study demonstrates that any Aspergillus sp. isolated for use as a fermentation starter should be analyzed for potential aflatoxin production using UPLC and HPLC for accurate quantitative analysis or ELISA for the rapid detection of low-level concentrations of aflatoxin.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.154-160
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• 2000

Aflatoxin B1 is known as the most potent mycotoxin produced by several fungi. It has been demonstrated to be not only carcinogenic but teratogenic and mutagenic as well in humans. To prevent or inactivate aflatoxins, several chemical of physical methods were tested for ammoniation, using insecticides as an wxample, but they were unsuitable for food products. On the contrary, biological control by antagonistic microorgani는 is and ideal method. In order to control aflatoxin B1 biologically, the antagonists #07, #63, #75, #74, and #61 were separated from various samples by using the antagonistic activity test. Among them, culture filtrate part A (non heat-treated) of #63 and #74 on aflatoxin B1 produced by Aspergillus fkavus were shown to be 95% and 75%, respectively. Based on the morphological characteristics, #63 was deduced as an Azospirillum sp.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.202-210
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• 2022

Aflatoxin contamination in rice has been documented in a number of studies, and has a high incidence in Asian countries, and as such, there has been a growing interest in alternative biocontrol strategies to address this issue. In this study, 147 strains of yeasts and yeast-like fungi were screened for their potential to produce volatile organic compounds (VOCs) active against Aspergillus flavus strains that produce aflatoxin B₁ (AFB₁). Five strains within four different genera showed greater than 50% growth inhibition of some strains of A. flavus. These were Anthracocystis sp. DMKU-PAL124, Aureobasidium sp. DMKU-PAL120, Aureobasidium sp. DMKU-PAL144, Rhodotorula sp. DMKU-PAL99, and Solicococcus keelungensis DMKU-PAL84. VOCs produced by these microorganisms ranged from 4 to 14 compounds and included alcohols, alkenes, aromatics, esters and furans. The major VOCs produced by the closely related Aureobasidium strains were found to bedistinct. Moreover, 2-phenylethanol was the most abundant compound generated by Aureobasidium sp. DMKU-PAL120, while methyl benzeneacetate was the major compound emitted from Aureobasidium sp. DMKU-PAL144. On the other hand, 2-methyl-1-butanol and 3-methyl-1-butanol were significant compounds produced by the other three genera. These antagonists apparently inhibited A. flavus sporulation and mycelial development. Additionally, the reduction of the AFB1 in the fungal-contaminated rice grains was observed after co-incubation with these VOC-producing strains and ranged from 37.7 ± 8.3% to 60.3 ± 3.4%. Our findings suggest that these same microorganisms are promising biological control agents for use against aflatoxin-producing fungi in rice and other agricultural products.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.36-41
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• 2016

Ochratoxin A and aflatoxin may be detected from naturally fermented foods due to the contamination of the mycotoxin-producing molds or un-prudential use of the mycotoxin producing starter strains during the fermentation. This study was carried out to analyze the production of ochratoxin A and aflatoxin under the various environmental conditions. For the experiment, the effects of different temperature, culture media, and fermentation time on the production of ochratoxin A by Aspergillus usamii KFRI 999 and A. awamori KFRI 983 were analyzed. Additionally, the production of aflatoxin was assessed under the various temperature, initial pH, fermentation time and culture media during fermentation by A. flavus KACC 41403 and A. oryzae KACC 46471. The levels of ochratoxin A and aflatoxin were analyzed by HPLC. The result showed that the production of mycotoxin was greatly affected by the fermentation temperature. A. oryzae KACC 46471 did not produce aflatoxin. All of the mycotoxin producing strains showed the highest level of mycotoxin at $30^{\circ}C$. A. awamori KFRI 983 showed the lowest level of ochratoxin A in PDA media among the experimental medium. The results of the present study may be useful for the reduction of ochratoxin A and aflatoxin in various foods.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.274-279
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• 2001

Generally, non-aflatoxigenic fungi, such as Aspergillus oryzae, and Aspergillus are main microflora in Korean traditional fermented foods including Meju and soybean paste, but sometimes, Aspergillus flavus and Aspergillus parasiticus can be contaminated and accumulated aflatoxins during fermentation and storage. So the screening of aflatoxigenic strains in fermented traditional food is very important to improve the sanitary quality of those foods. In this work, we screened aflatoxin producing fungi from commercial Meju and soybean paste in Western Gyeongnam by immunoassay. Samples were randomly purchased from market of the commercial Meju(10 EA) and soybean paste(20 EA) in nine areas of Western Gyeongnam. Of the samples collected,24 strains and 22 strains of Aspergillus sp. were isolated from Meju and soybean paste, respectively. The isolated strains were cultured on SLS media at $25^{\circ}C$ for 15 days. The cultured broth were extracted with ethyl acetate and were analysed to determine aflatoxin B$_1$(AFB$_1$) by direct competitive ELISA(DC-ELISA). Six strains(25%) isolated from Meju, and 2 strains(9%) isolated from saybean paste, were confined as aflatoxin producing strains. The average range of aflatoxin productivity of isolates from Meju was 54.6 $\pm$ 38.7 ng/ml and that from soybean paste was 11.1 $\pm$ 8.6 ng/ml, respectively. Among them, isolated strain No. M-5-4 produced a high level of AFBl and showed 98.26 ng/ml of AFB$_1$. Every isolates were also re-confined their AFB$_1$productivity by thin layer chromatography(TLC). The TLC results also showed same trend as DC-ELISA results. As the above results, the screening of hazard mycotoxigenic fungi from traditional fermented foods should be necessary for the safety and the application of HACCP system in the food manufactory in Korea.

• The Korean Journal of Mycology
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• v.8 no.1
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• pp.59-62
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• 1980

Investigation on modification of aflatoxin structures by Pseudomonads was attempted as a biological detoxifiying process of mycotoxins. Firstly, when any variation of aflatoxin yield of Aspergillus parasiticus in a mixed culture with Pseudomonas aeruginosa was examined, there was no noticible effect by growth of Pseudomonads on aflatoxin yield of Asperillus sp. Secondly, when capacity of Pseudomonas aeruginosa utilizing aflatoxin as a carbon source for its growth was tested, there was some indication that aflatoxin might be used for growth of Pseudomonads. It was also noticed that the residual aflatoxin showed different migrating pattern compared with that of the intact aflatoxin by thin layer chromatography. Thirdly, the cell-free extract prepared from Pseudomonas aeruginosa grown in a glucose minimal medium supplemented with aflatoxin and the intact aflatoxins were incubated in the presence of $Mg^{++}$. After a certain length of incubation period, the reaction mixtures were applied on TLC plates. As a result, aflatoxins in the reaction mixture migrated differently as the control did. Such results may indicate that some changes of aflatoxin properties were induced by Pseudomonads.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.13-14
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• 2001

Doenjang (Korean fermented soybean paste) is one of important fermented foods in Korea. Doenjang has been traditionally manufactured from meju which is fermented rectangular shape of crushed cooked soybeans. The main microorganisms involved for meju fermentation are Bacillus subtilis and molds such as Rizopus sp., Mucor sp. and Aspergillus sp. We have already reported that Doenjang is free from mycotoxin, especially, aflatoxin B$_1$contamination during the manufacturing process of the Deonjang.(omitted)

• Journal of the East Asian Society of Dietary Life
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• v.6 no.1
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• pp.105-114
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• 1996

Certain Fungi Including Aspergillus flavus produce low molecular secondary metabolite that is toxic to human and animals, which have been termed mycotoxin. Given the proper humidity and temperature like summer in Korea, are capable of growing of those hazard fungi and elaborating mycotoxin on almost any organic substrate such as traditional foodstuffs and their raw materials including rice, barley, corn, meju, doenjang and gochujang etc. Until now, some people have examined to isolate various fungi such as Aspergillus sp., Penicillium sp. and Fusarium sp. from traditional foodstuffs and raw materials, and have screened various mycotoxin producing strains. Some mycotoxin contamination such as aflatoxin, ochratoxin, deoxynivalenol (DON) and zearalenone etc. also have been confirmed from similar above samples. But these data are different each other and inconsistent in experimental conditions and methods. Especially, almost experiments have been finished for one time. So more consistent experimental method and data are necessary to evaluate objectiely the safety of traditional foodstuffs subjected to the mycotoxin. For this purpose, we have to apply a new advanced technology to develop more simple and rapid methods for determination of mycotoxin and also have to concentrate our efforts on activation of research and accumulation of technology nth sustaining investment of financial support and enlargement of research installation. With those harmonious efforts, it should be possible to examine continuously nd systematically the mycotoxin contamination in our traditional foodstuffs and to assure the safety of them. Then we can maintain and develop the better traditional foodstuffs suited to internationalization.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1258-1265
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• 2000

In oder to acquire microbial agents that can be utilized for control of aflatoxin produced by Aspergillus. flavus and Asp. parasiticus, antifungal bacteria were isolated. Antifungal bacteria was identified as Bacillus spp. based on morphology and physico-biochemical characteristics. Amount of aflatoxin $B_1$ from Doenjang(soybean paste) prepared with Asp. flavus, Asp. parasiticus, antifungal bacteria(Bacillus sp.), or mixture of Asp. flavus and Asp. parasiticus was 27.2 ppb, 30.3 ppb, 3.4 ppb, and 3.7 ppb, respectively. Aflatoxin $B_1$ was not detected from Doenjang(control) and Doenjang prepared with antifungal bacteria. Content and compositions of free sugars, fatty acid, organic acid and free amino acid in Doenjang prepared with Asp. flavus and Asp. parasiticus, antifungal bacteria and mixture of Asp. flavus and Asp. parasiticus were not significantly different. For volatile flavor compounds of Doenjang prepared with antifungal bacteria, 2-pentyl furan and butanoic acid were disappeared or reduced, while octadecene compounds were produced. However, those of Doenjang prepared with Asp. flavus or Asp. parasiticus and Doenjang(control) were not significantly different. These results suggested that the antifungal bacteria(Bacillus sp.) inhibited production of aflatoxin and that antifungal bacteria did not effect the quality of Doenjang.