• Research in Plant Disease
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• v.20 no.4
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• pp.289-294
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• 2014

Rice samples including paddy, husk, brown rice, blue-tinged rice, broken rice, discolored rice and polished rice were collected from rice processing complexes(RPC) nationwide to determine the contamination of fungi and mycotoxins on rice during 2010-2013. Among the samples, paddy rice had the highest frequencies of fungal and Fusarium occurrence, and the frequencies decreased along with milling as husk was the next. Blue-tinged rice or discolored rice was similar with brown rice for fungal occurrence, and polished rice showed the lowest frequency. Among Fusarium species, F. graminearum species complex occupied 87% in 2012 but did 35-39% in 2011 and 2013. Aspergillus and Penicillium species appeared at low frequency in most samples but occurred at higher frequency in certain RPC samples. Alternaria, Nigrospora, and Epicoccum species occurred similarly to the pattern of total fungi. The rice samples from 2010-2012 were analyzed for the occurrence of Fusarium mycotoxins including deoxynivalenol, nivalenol, zearalenone, and other trichothecenes. The most highly contaminated sample was discolored rice in terms of frequency, level, ratio of simultaneous contamination with multiple toxins, followed by blue-tinged rice.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.779-785
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• 1996

Sansung takju, the Korean traditional liquor at a local area of Sansung in Pusan, has been widely drunken due to its tradition in this area. The studies on microorganisms of kokja, fermentation process and shelf-life of takju were carried out. The most abundant microorganism identified from a commercial Sansung kokja was Aspergillus, Mucor, Rhizopus and Penicillium were also identified. In case of a home-made Sansung kokja, Mucor was the most abundant one. Aspergillus, Rhizopus and Absidia were also identified in it. Saccharomyces, Micrococcus and Bacillus were identified in both kokja's but acid production bacteria were not found. Ethanol fermentation was carried out at $25^{\circ}C$ and $30^{\circ}C$ using each kokja. The rate of ethanol production was faster at $30^{\circ}C$ than at $25^{\circ}C$, while higher viable yeast count and final ethanol content were obtained at $25^{\circ}C$ than at $30^{\circ}C$. The ethanol contents of the mashes using a commercial Sansung kokja and a home-made Sansung kokja after 14 days at $25^{\circ}C$ were 11.0% and 12.4%, respectively. The shelf-life of takju was affected more by ethanol content in the product than by storage temperature. The product stored at $-15^{\circ}C$ did not change significantly in acidity but tasted watery due to thawing. In case of Sansung takju containing 6%ethanol, level of acidity increased and pellicle was formed on the surface of the product during storage at $30^{\circ}C$. In case of Sansung takju containing 9% or 12% ethanol, no significant changes in acidity and appearance were observed for 14 days at $30^{\circ}C$.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.288-291
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• 2012

Korean oak wilt disease caused by Raffaelea quercus-mongolicae is vectored by the ambrosia beetle Platypus koryoensis. To prevent the spread of the disease, the beetle infested oak tree had been cut into logs, covered with plastic vinyl, fumigated with a pesticide, and stored for three years on the site where the tree was cut. This study was carried out to get information on the fungi colonizing the fumigated oak wood. Wood disk samples collected from the fumigated oak logs at two locations in the Taejo Mountain, Cheonan city, were used for fungal isolation. A total of 99 filamentous fungal isolates were obtained from the wood disk samples. Hypocrea spp., Trichoderma spp. and Penicillium spp. were identified based on morphological characteristics and nucleotide sequence analysis of translation elongation factor 1-alpha gene and ITS rDNA region. Trichoderma was the major fungal group. R. quercus-mongolicae, and P. koryoensis were not detected from the fumigated oak wood. Our work provided evidence that after three years of storage, the fumigated oak wilt-diseased logs should be no longer harmful source of oak wilt disease transmission.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.387-393
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• 2012

In order to improve storability of subtropical yam produced in South Korea, the major pathogens found during the storage were isolated and identified of the pathogenicity, and rot inhibition effect was studied based on the curing treatment condition. Penicillium sclerotigenum and Penicillium polonicum were identified as major pathogens causing rot in subtropical yam during storage, and P. sclerotigenum had stronger pathogenicity. Only the cut surface which has been made during a harvest and has been made smooth before curing generated a normal callus layer. The cut surface of tuberous root was cured in 95% of relativity humidity for three days at $23^{\circ}C$, and cured at $28^{\circ}C$ and $33^{\circ}C$. The observation of callus layer showed that the $23^{\circ}C$ treatment group had similar color saturation between tuberous root and pellicle, while the groups treated above $28^{\circ}C$ showed clear distinction. The generation rate of callus 0.5mm or bigger was 93 percent at $28^{\circ}C$ treatment, 96% at $33^{\circ}C$ treatment, but was 52% at $23^{\circ}C$ treatment. The conventional curing treatment group that used wind or sunlight at room temperature created little callus layer. The infection rate of pathogens according to the relative humidity inside the storage room was low at 40% and 60% of humidity, and the curing treatment period did not make a difference. When the humidity inside the storage room was 80%, all treatment groups rapidly increased the fungal pathogens. The rotten rate of each treatment was studied after 180 days during which the storage temperature was maintained at $16^{\circ}C$ and relative humidity 60%. While the rotten rate of tuberous root that has been cut in conventional curing treatment based on solar and wind was 43%, the one cured at over $28^{\circ}C$ and created the callus layer was less than 18%. While even a healthy tuberous root showed 25% of rotten rate in the traditional treatment group, the one cured at over $28^{\circ}C$ was less than 10%. The weight loss was 1-6% lower in the forced treatment group than in the conventional treatment group.

• 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 $G_2$, $(45-112\;{\mu}g/kg)$.

• KSBB Journal
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• v.11 no.3
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• pp.317-322
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• 1996

Galactooligosaccharlde (GOS) is a kind of functional oligosaccharides that can be used as a food ingredient and a cosmetic additive. In this paper, characteristics of GOS synthesis by cellulase, using lactose as a substrate, were investigated. Penicillium funiculosum cellulose was found to be the most efficient for GOS production among six cellulose tested. The optimum pH and temperature for GOS production were 5.0 and $50^{\circ}C$, respectively. There was an optimum ratio of lactose concentration to enzyme loading; the value was 10 (w/w). The reaction pattern of P. funiculosum cellulase is consistent with that of microbial ${\beta}$-galactosidase which shows transgalactosylation activity. Amounts of GOS produced from 20% (w/v) lactose after 6 h incubation at $50^{\circ}C$, were 23% (w/w) based on total saccharide in the reaction medium. The GOS % increased with initial lactose concentration in the range of 5 to 20%. The products mainly consisted of a trisaccharide and tetrasaccharide from HPLC and TLC analysis. Among enzymes involved in transgalactosylation reaction, high molecular weight fractions over 50,000 Da, presumably ${\beta}$-glucosldase, were considered to be responsible for GOS production. Using this cellulose, a direct synthesis of galactosyl g1ucoside including GOS could be readily achieved with lactose as a galactosyl donor.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.338-345
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• 1994

In the course of developing a small composter for dwelling house, we designed two different small bins; one is insullated (type 1) and the other uninsullated (type 2). Several interesting results were abtained from the study using these bins for garbage composting in winter, spring and summer. Changes in microbial number were very similar to those observed in the general composting process. However, microbial flora was relatively simple. The genera Streptomyces and Nocardia of actinomycetes and the genera Aspergillus, Penicillium, Mucor, Absidia, Rhizopus of hypomycetes was observed from the composted materials. Thermophiles secreted most of the ${\alpha}-amylase$ secreted in winter but mesophilic actinomycetes did in summer. The amount of secreted protease was much lower in winter than in summer. Lipases were secreted more by mesophiles than thermophiles. Only Aspergillus of hypomycetes was observed to degrade cellulose. Generally, the appearance of enzyme producing microorganisms increased in summer than in the other seasons. In the point of seasonal increase of temperature and changes in microbial flora, the number of microorganisms was higher in summer or spring than in winter.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.153-157
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• 2001

The relationship between SPM (Suspended Particulate Matter) and fungal spore in the air was investigated in Seosan, a rural county of Korea, in spring of 2000. SPM concentrations in the air were $199.8\mu{g}\;m^{-3}$, in the 1st Yellow Sand Period (March, 23-24), $249.4\mu{g}\;m^{-3}$ in the 2nd Yellow Sand Period (April, 7-9) and $98.9\mu{g}\;m^{-3}$ in the Non Yellow Sand Period (May, 12-16), respectively. Although there was somewhat difference in total SPM concentration between the two Yellow Sand Periods, majority of the total SPM were composed of $5\mu{m}$ sized coarse particles over the two periods. However, fine particles sized about $1\mu{m}$and coarse particles sized about $5-6\mu{m}$ ultimately showed peaks, which was within typical bimodal pattern at the graph of SPM size distribution in the Non Yellow Sand Period. Four mold genera grown from airborne fungal spores were finally identified in full-grown colonies at the SPM samples during the Yellow Sand Periods. These genera were Fusarium, Aspergillus, Penicillium and Basipetospora.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.281-287
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• 2013

In Korea, isolated cultivation has been implemented for 102 genera, including about 250 species, each of which has underwent microscopic inspection, cultivation of bacteria in selective medium, analysis of physiology and biochemistry, enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). The number of isolated microorganisms was 8,307 in the period of 2005-2012, and bulbs and tubers had the greatest diversity of microorganisms, of 5,165 (62.2%), followed by 2,119 (25.0%) sapling, 796 (9.6%) seed, 150 (1.8%) cutting slip, 70 (0.8%) branch graft and 7 (0.1%). The number of cases which were disqualified were 413 (4.97%), after the detection of 47 disease causing species of microorganism. Viruses predominated, with 27 species, followed by 16 fungi, a viroid, a Chromalveolata and 2 further species. Top on the list of detection was Arabis mosaic virus (77 cases), followed by Tobacco rattle virus (70 cases), Lily symptomless virus (46 cases) and Penicillium expansum (46 cases).

• Journal of Food Hygiene and Safety
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• v.2 no.3
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• pp.97-102
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• 1987

The effects of gamma irradiation on microbiological and physicochemical qualities in raw ingredients (thirteen kinds of cereal grain and their by-product) of mixed feeds were investigated. The total aerobic bacteria counts in the samples were $10^2\;to\;10^6/g$. They were sterlllzed to a undetectable level by 5 to 7 kGy irradiation. Coliforms were contaminated in high levels in all sample, ranging from $10^2\;to\;10^6/g$. They were radiation-llensitive and completely eliminated by irradiation with 3 to 5 kGy. Total fungi, ranging from $10^2\;to\;10^4/g$, mainly osmophiles were identified as Aspergillus and Penicillium. They were eliminated below identification limit by 5 to 7 kGy irradiation. Seven kinds of species, including Aspergillus IkrlJUB. were identified as a potential mycotoxin producers. Physicochemical qualities, such as total amino acid content, total sugar content. TBA value and color difference showed that an optimum dose of irradiation was less detrimental than ethylene oxide fumigation.