• Applied Biological Chemistry
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• v.15 no.3
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• pp.193-198
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• 1972

Twenty seven specimens of deteriolated storage rice were collected all over Korea. Types of deteriolation were classified according to color outlooks, and for 48 grains of each specimen the causative storage microorganisms were isolated and identified. The following results were observed; 1. 27 specimens of deteriolated rice were classified according to color outlooks into 7 types: reddish yellow 1, light reddish yellow 3, light grayish yellow 4, light red 6, dark gray 7, light gray 3, and rice weevil type 3. 2. The most common storage microorganisms group which infected deteriolated Korean rice were Aspergillus glaucus group, especially species of A. amstelodami, A. chevalieri, A. montevidensis, and A. ruber, which were frequently associated with Penicillium, Brevibactereum, and Bacillus. 3. As a specific case sometimes a specimen of deteriolated rice was infected chiefly by one deminant species of microorganism. Five cases were observed: that is, by P. islandicum, P. lanosum, B. lentus, Pseudomonas cohaerans, Brev. lipolyticum. 4. No definite relationship was observed between color outlook types and the deteriolation causing microorganisms. Only the heavily infected rice by Penicillium islandicum expressed discernible reddish yellow color indicative of the infection by this mold. 5. Mycotoxin problem could be noted in one specimen of deteriolated imported rice heavily infected by P. islandicum. Other mycotoxin producing fungi, A. flavus, A. ochraceus, A. fumigatus were also detected, but their growth frequencies were so low that it might not be serious problem.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.194-200
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• 2016

Aflatoxins and ochratoxin A (AFTs and OTA) are secondary fungal metabolites produced by several moulds, mainly by Aspergillus flavus by Aspergillus ochraceus and Penicillium verrucosum, and these toxins can be transferred to animals and humans through the ingestion of contaminated feed and food. This study was to develop the analytical method for determination the levels of AFTs ($B_1$, $B_2$, $G_1$ and $G_2$) and OTA in pork. The AFTs and OTA were analyzed simultaneously by electrospray ionization in positive ion mode and mass reaction monitoring (MRM) after solid phase extract (SPE) columns clean-up. Performance characteristics, such as accuracy, precision, linear range, limit of detection (LOD) and quantification (LOQ), were also determined. Matrix-matched standard calibration was used for quantification, obtaining the recoveries in the range of 67.3~108.2% with the relative standard deviations of < 20%. Limits of detection and quantification were also estimated, obtaining the limits of quantification ranged in $0.7{\sim}1.3{\mu}g/kg$. The results of the inter-day study, which was performed with pork samples for 3 days, showed an accuracy of 92.0~109.9%. The precisions (expressed as relative standard deviation values) for the inter day variation were 2.6~17.8%. The method developed in this study was able to carry out the analysis with the satisfactory intensity and accuracy.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.339-346
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• 2007

The MJP1 bacterial strain, which possesses antifungal activity, was isolated from meju and identified as Bacillus subtilis based on its morphological and biochemical properties, as well as its 16S rRNA sequence. Antimicrobial activity was found against various species of Gram-positive bacteria, yeasts, and molds, including food-spoilage microorganisms. The antifungal activity was found to be stable after heat and proteolytic enzyme treatment, and in the pH range of $6.0{\sim}10.0$. The antibacterial activity was stable in the pH range of $6.0{\sim}10.0$, but about 50% of the activity was lost after 24 hr at $30^{\circ}C$. The antibacterial compound was also inactivated by proteolytic enzyme treatment, indicating its proteinaceous nature. The apparent molecular masses of the partially purified antifungal and antibacterial compounds, as indicated by using the direct detection method in Tricine-SDS-PAGE, were approximately 2.4 kDa and 4.5 kDa, respectively. These studies suggest that B. subtilis MJP1 produces two bacteriocin-like substances with antifungal and antibacterial activities.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.189-196
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• 1982

Seventy two samples of feedstuff were collected from commercial channels all over Korea. As a study on the moisture contents, microflora and mycotoxin production of each sample investigated. Moisture content of the samples was $11.2{\sim}15%$. Total counts of the samples were $1.8{\times}10^{2}{\sim}2.4{\times}10^{6}$ per gram. The Coli-form group were counted from 9 to $6.3{\times}10^{5}$ per gram which composed mainly of Enterobacter and Klebsiella, whereas Escherichia coli was minor ones. The contamination of many feeds was not remarkable, and only some broiler feeds was contaminated largely with Escherchia coli. Fungi were below detectable limit in 45% of the samples and the most contaminated sample had $4.5imes}10^{5}/g fungi counts.

• Korean Journal of Food Science and Technology
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• v.14 no.1
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• pp.67-71
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• 1982

Mutant strans of Salmonella typhimurium which require histidine for their growth sensitively, were easily revertant and lost the histidine requirement, when the strains contacted with some new mutagen. This work was carried out to determine the mutagenicity of kojic acid and emodin for the mutant strains of Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537, and TA 1538. Through the metabolic activation with liver microsome enzyme system of rat (S-9), kojic acid was recognized as a strong mutagen for the strain of TA 98, while it responsed weakly for the strain of TA 100. Without S-9 metabolic activation, kojic acid could not induce the mutation for the both strains of TA 98 and TA 100. Emodin was also recogniged as a strong mutagen for the strain of TA 1537 through the metabolic activation with S-9 mix.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.535-542
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• 2018

The current study investigated the beneficial effects of 15 essential oils isolated from tree branches, leaves, and flowers. Among these oils, clove bud and Illicium anisatum oils showed the most potent anti-oxidant effects on 1,1-diphenyl-2-picrylhydrazyl and 2,2'azinbis-(3-ethyl-benzothiazoline-6-sulfonic acid) radical scavenging activities. Next, we evaluated the antibacterial effects of 15 essential oils on Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, Salmonella typhimurium, and Streptococcus mutans. Clove bud significantly decreased growth of 5 bacterial strains. In addition, clove bud, Magnolia kobus, Picea abies and Chamaecyparis obtuse significantly reduced growth of the fungi, Aspergillus fumigatus, Aspergillus ochraceus, Candida albicans and Trichophyton rubrum. Additionally, clove bud also remarkably reduced the expression of cyclooxygenase-2 and inducible NO synthase in lipopolysaccharide-activated RAW264.7 cells. These results indicate that essential oils isolated from trees, which exhibit antioxidant, antibacterial, antifungal and anti-inflammatory properties, may be potentially useful in the development of cosmetic ingredients.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.121-128
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• 1998

Ochratoxin A (OA) is a mycotoxin produced by Aspergillus ochraceus as well as other molds. It is a natural contaminant of mouldy food and feed. OA has a number of toxic effects, the most prominant being nephrotoxicity. Futhermore, OA is immunosuppressive, genotoxic, teratogenic and carcinogenic. OA inhibits protein synthesis by competition with phenylalanine in the phenylalanine-tRNA aminoacylation reaction. Recently, lipid peroxidation induced by OA has been reported, indicating that the lesion induced by this mycotoxin could be also related to oxidative pathway. Since it seems impossible to avoid contamination of foodstuffs by toxigenic fungi, detoxification and detoxication of OA are needed. In this study we investigated the protective effects of aspartame (Asp), phenylalanine (Phe), polyphenol 70S (PP) and aloe extract (AE) on the nephrotoxicity induced by subacute exposure to the OA. Asp and Phe are structural analogues of OA. PP, an ingredient of Green Tea and AE have been known as antioxidant and radical scavenger. Phe (40 mg/kg, i.p.) and Asp (25 mg/kg, p.o.) were administered to Sprague-Dawley rats simultaneously with OA (2.0 mg/kg, p.o.) for 2 weeks. PP (200 mg/kg, p.o.) and AE (50 mg/kg, i.v.) were pretreated before administration of OA, for 2 weeks and 3 days, respectively. Using enzymuria, BUN level, creatinemia and histophathologic examination as indices of renal damage, we observed that all of four compounds prevented the nephrotoxic effects induced by OA. It seems that structural analogues of OA such as Asp and Phe have better protective effect on the nephrotoxicity of OA than antioxidants. These results indicate that 1) formation of free radical and lipid peroxidation are likely to be involved in the nephrotoxicity of OA in vivo, 2) Asp, PP and AE might be used for prevention of renal lesions in cases of ochratoxicosis.