• Journal of Life Science
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• v.31 no.5
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• pp.481-487
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• 2021

The purpose of this study was to identify fungi that degrade product value during the storage and distribution of confectionery products, and to investigate the antifungal effect of organic acid and UV-C treatments on high carbohydrate products. Fungi isolated from spoiled high carbohydrate confectionery were identified as Wallemia sp., Aspergillus sp-1 and Aspergillus sp-2 depending on homologies with ITS1 and ITS4 sequences. The isolated fungi were assayed for antifungal activity by treatment with acetic acid, citric acid, lactic acid or maleic acid. As a result, it was confirmed that the growth of Wallemia sp. and Aspergillus sp-2 was suppressed by treatment with 0.2 M and 0.35 M acetic acid, respectively. In addition, as a result of confirming the antifungal effect according to the UV-C irradiation time, the growth inhibitory effects of Wallemia sp. and Aspergillus sp-2 were shown in irradiation for 30 min and the growth inhibitory effect of Aspergillus sp-1 was shown in irradiation for 40 min. The result of the sensory evaluation of the untreated and 0.35 M acetic acid-treated high carbohydrate confectionery, there were not significant changes in taste, color, abnormal taste, hardness and texture, but there were significant differences in sour taste and smell. As a result of the above study, the effect of inhibiting fungi growth on the product by treatment with organic acid and UV-C irradiation was confirmed, and it is expected to be used in confectionery that were concerned about the occurrence of fungi in the distribution process.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.132-139
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• 2005

The major obstacle in the popularization of Chungkookjang is the short shelf-life of $2{\sim}3$ months and some problems concerning storage including the growth of molds even in the products even within shelf-life. To solve these problems we conducted a research to improve its storage by using the vacuumed packaging and sanitary method through seed culture, innoculation and sterilization. For the optimization of storage time, temperature and sterilization temperature, we measured viable cell numbers of bacteria and fungi, amount of gas outbreak and contents of amino type nitrogen and monitored these experimental results by response surface methodology of SAS program, so that we could observe the quality changes of Chungkookjang during shelf-life. Especially fungi, which are the biggest troublemaker in Chungkookjang shelf-life, couldn't be detected from the generally and vacuum-packed samples; also, viable cell numbers were highly influenced by sterilization temperature and in vacuum-packed samples. In the case of vacuum-packed samples, amount of gas outbreak was highly influenced by sterilization temperature of its storage conditions and it was higher in generally packed samples as compared to vacuum-packed samples even at any storage conditions. The changes of pH in generally and vacuum-packed samples were highly influenced by the storage temperature. As the temperatures of storage and sterilization were higher and the storage time was longer, so the amount of gas outbreak was accordingly lower. These results showed that amino type nitrogen contents in generally and vacuum-packed samples were systematically influenced by the temperature, storage time and sterilization temperature. Also the result showed that the change of amino type nitrogen contents during storage was less in vacuum-packed samples than in general ones. Based on the above results, we can produce Chungkookjang products with extended shelf-life of as far as 6 months without any quality change using sanitary manufacturing method, vacuumed packaging condition, sterilization in $70^{\circ}C$ for 60 minutes and storage under $10^{\circ}C$ during shelf-life. According to this research, we have the possibility to greatly increase the goods value of Chungkookjang by developing the manufacture processing and packaging.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.191-196
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• 1982

In order to prevent the losses of the rice by fungal deterioration during storage, fungal contaminants were isolated and identified from the grain samples (Milyang Nr.23) stored for seven months from December, 1978 to June, 1979 in silo, flat store and Tongari. Out of thirty cultures isolated from Korean paddy and brown rice samples, twenty seven species were identified, and there are eleven species of Aspergillus (A. caespitosus, A. condidus, A. chevalieri, A fischeri, A. fumigatus, A. flavus, A. nidulans, A. oryzae, A. ruber, A. sydowii, A. versicolor), five species of Penicillium (P. atramentosum, p. chrysogenum, P. cyaneofulvum, P. nototum, P. steckii), two species of each Alternaria (Al. faesiculata, Al. grisea) and Curvalaria (C, interseminata, C. tetromea), and one species of each Trichothecium roseum, Nigrospora sphaerica, Rhizopus nigricans, Fusarium spp., Mucor spp., Helminthosporium spp., and Gliocladiopsis spp. The major types of fungi grown on the surface of paddy during storage were A. flavus and A. candidus, while A. ruber and A. sydowii appeared in brown rice samples. And also A. candidus, A. versicolor and A. glacus groups were considered as major deteriorating microorganisms in stored brown and paddy rice in Korea.

• The Plant Pathology Journal
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• v.24 no.3
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• pp.322-327
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• 2008

Antifungal activities of natural substrances from Eucalyptus darlympleana, E. globules, E. gunnii and E. unigera were evaluated against postharvest pathogens of kiwifruits, Botrytis cinerea, Botryosphaeria dothidea, and Diaporthe actinidiae, to screen effective natural substances as an alternative to chemical fungicides. Methanol extract of the Eucalyptus trees showed strong antagonistic activity against the pathogenic fungi. Among them, E. unigera and E. darlympleana effectively inhibited mycelial growth of the pathogens. For chemical identification of the antifungal substances, the methanol extract of E. darlympleana leaves was successively partitioned with $CH_2Cl_2$, EtOAc, n-BuOH and $H_2O$. Among the fractions, $CH_2Cl_2$ and n-BuOH showed strong inhibitory activity of mycelial growth of the fungi. Five compounds were isolated from EtOAc and n-BuOH fractions subjected to $SiO_2$ column chromatography. Two phenolic compounds(gallic acid and 3,4-dihydroxybenzoic acid) and three flavonoid compounds(quercetin, quercetin-3-O-$\alpha$-L-rhamnoside, quercetin-3-O-$\beta$-glucoside) were identified by $^1H$-NMR and $^{13}C$-NMR spectroscopy. Among them, only gallic acid was found to be effective in mycelial growth and spore germination of B. cinerea at relatively high concentrations. The results suggest that gallic acid can be a safer and more acceptable alternative to current synthetic fungicides controlling soft rot decay of kiwifruit during postharvest storage.

• Food Science and Preservation
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• v.11 no.4
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• pp.437-440
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• 2004

To investigate the effects of pre-treatment and packaging materials for dried persimmon during 6 month storage, the citric acid, salt, xylitol, L-cystein was pre-treated on dried persimmon, and then packed with LDPE film($0.06\;{\mu}m$) and N/LDPE($0.06\;{\mu}m$). The rate of moisture contents, browning, fungi and weight loss of dried persimmon pre-treated with citric acid, salt, xylitol, L-cystein were changed a little in N/LDPE, but were highly changed in LDPE. The commodity of dried persimmon packed with N/LDPE was also higher than that of LDPE.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.268-277
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• 1998

The production of Korean ginseng, one of the most important medicinal root crops, is limited by many factors including soil sickness, root rots in fields as well as during storage prior to consumption. Although much research has been conducted on the diseases in field condition, little information is available on the control of postharvest roots rots. To obtain better management strategy of postharvest root rots in ginseng, biological control using antagonistic bacteria was attempted. Of 208 bacteria obtained form suppressive soil samples, 4 were selected based on the inhibitory effect on mycelial growth of two major causal fungi for postharvest root rots in ginseng, Botrytis cinerea and Fusarium solani. The culture filtrates of these bacterial antagonists greatly inhibited the conidial germination of both pathogenic fungi and produced abnormal morphology such as swollen germ tubes in F. solani and vacuolation of nongerminated conidia in B. cinerea. The population levels of bacterial antagonists on the ginseng roots were gradually increased up to 8 days of incubation. Postharvest root rots of ginseng caused by f. solani and B. cinerea were controlled in dipping tests in the ranges of 60∼80% by antagonistic Bacillus spp. obtained from suppressive soil. These results suggest that biological control using these antagonistic bacteria would be an alternative strategy to control postharvest root rots in ginseng.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.286-289
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• 2000

Mechanol extracts of three cold-tolerant eucalyptus trees-Eucalyptus darlympleana, E. gunnii and E. unigera were screened for antimicrobial activity against twenty two phyto-pathogenic fungi and six food-borne bacterial pathogens. E. unigera showed the antagonistic activity against all the tested pathogens. Among the tested fungal pathogens, Pythium species were highly sensitive to the leaf extracts. Especially, P. vanterpoolii, a causal agent of leaf blight in creeping bentgrass (Agrostis palustris), was completely inhibited by the extracts. The eucalyptus extracts were also effective in inhibiting the fungal growth of Botrytis cinerea and Phomopsis sp. isolated from the lesions of kiwifruit soft rot during post-harvest storage. Escherichia coli O-157 was less sensitive to the inhibition than the other bacterial pathogens tested. It was likely that Gram positive bacteria-Bacillus subtilis and Streptococcus mutans were more sensitive to the eucalyptus extracts than Gram negative bacteria-Escherichia coli, Salmonella enteritidis and Pseudomonas aeruginosa. Our findings suggest that the cold-tolerant eucalyptus species have antimicrobial properties that can serve the development of novel fungitoxic agents or food preservatives.

• Journal of Dairy Science and Biotechnology
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• v.37 no.2
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• pp.83-93
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• 2019

Food spoilage by fungi is responsible for considerable food waste and economical losses. Among the food products, fermented dairy products are susceptible to deterioration due to the growth of fungi, which are resistant to low pH and can proliferate at low storage temperatures. For controlling fungal growth in dairy products, potassium sorbate and natamycin are the main preservatives used, and natamycin is approved by most countries for use in cheese surface treatment. However, a strong societal demand for less processed and preservative-free food has emerged. In the dairy products, lactic acid bacteria (LAB) are naturally present or used as cultures and play a key role in the fermentation process. Fermentation is a natural preservation technique that improves food safety, nutritional value, and specific organoleptic features. Production of organic acids is one of the main features of the LAB used for outcompeting organisms that cause spoilage, although other mechanisms such as antifungal peptides obtained from the cleavage of food proteins and competition for nutrients also play a role. More studies for better understanding these mechanisms are required to increase antifungal LAB available in the market.

• The Plant Pathology Journal
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• v.24 no.3
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• pp.309-316
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• 2008

Mycelium of Ophiostoma quercus albino strain cultured in liquid culture media was harvested, lyophilized, and stored for examining biocontrol efficacy against wood discoloration by staining fungi in the laboratory and field conditions. Dry weight of mycelium grown in brown sugar yeast extract broth(BYB) showed 3.8 times higher than that grown in potato dextrose broth(PDB). The optimum culture period in BYB was 4 weeks. In vitality test of the albino strain, the lyophilized mycelium stored in liquid nitrogen($-196^{\circ}C$) or in a refrigerator($4^{\circ}C$) kept the vitality until 13 months after storage; however, the mycelium stored at room temperature lost the vitality completely after 13 months. The mycelium stored in liquid nitrogen or in a refrigerator protected wood chips from the discoloration by pretreating mycelial suspension on pine wood chips. The mycelium stored at room temperature for 7 months also showed complete protection. These results suggest that the lyophilized mycelium have a biocontrol efficacy only if it keeps the least vitality. In the field conditions, both albino strain and $Woodguard^{(R)}$(commercial chemical protectant) showed significant differences(p=0.05) in discoloration rate as compared to the non-treated control when these were treated on the wood logs of Pinus rigida. The albino strain showed better protection than $Woodguard^{(R)}$. Isolation frequency of blue stain fungi from the chips of wood logs treated with the albino strain was 0% at three months after treatment, while that treated with $Woodguard^{(R)}$ was 76.7%. In another experiment, pre-treatment of mycelial suspension on the cut surface of wood logs also showed significant protection from wood discoloration. Spraying of both albino strain on the cut surface and insecticides on the bark also showed relatively good control effects as compared to insecticide alone on the bark or nontreated control.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.297-305
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• 1982

Environmental conditions of fungal growth on Korean rice grain, Milyang No.23, were studied and optimum treatment conditions of the selected fumigants for controlling fungal deterioration of rice were investigated The results are as follows. 1. Most of the fungi grew well above 80% relative humidity and 19% moisture content within 10-30 days. But at 12.5-13.0% moisture content of grains, only Aspergillus candidus, Asperillus versicolor, Penicillium chrysogenum, and Trichothecium roseum were developed within 2 months. The other fungi were only detectable for their mycelial growth under microscopic observation. 2. Among the ten fumigants tested to control the fungal growth on the rice, ethylene oxide was found to be the most effective at a leve1 of 16 mg/$\ell$ for 48 hrs treatment and the next was methyl bromide (32 mg/$\ell$), acrilonitrile and methyl iodide (64 mg/$\ell$). The other fumigants, such as ammonia, methyl formate, ethyl formate, carbon dioxide and propionic acid were found less effective under the tested conditions.