• The Plant Pathology Journal
• /
• v.26 no.2
• /
• pp.121-129
• /
• 2010

We evaluated microbial populations and aflatoxin production in unhulled and white rice from rice processing complexes of the National Agricultural Cooperative Federation in five regions in Korea and identified three predominant Aspergillus species. Fungal and bacterial populations in rice samples were significantly different between regions in 2007. Aflatoxins were also detected and varied at the levels of 2.45 - 3.43 ng per g unhulled rice grain and 1.29 - 2.09 ng per g white rice grain. Unhulled rice generally detected higher level of aflatoxins than white rice regardless of sampling regions; however, no significant differences were found in Anseong and Cheonan in 2005 and Cheonan and Gimpo in 2007. Aflatoxin production between sampling regions was not different regardless of rice type and sampling year. Although the fungal diversity was highly distinct from region to region, three Aspergillus isolates were predominant in the rice samples; thus, representative isolates AC317, AF57, and AF8 were selected and identified based on their morphological and molecular characteristics. Consequently, isolates AC317, AF57, and AF8 were identified as A. candidus, A. flavus, and A. fumigatus, respectively. These fungi can produce mycotoxins that are harmful for consumers and thus it is important to detect and reduce the population of storage fungi in rice.

• The Plant Pathology Journal
• /
• v.34 no.5
• /
• pp.356-366
• /
• 2018

The red flour beetle, Tribolium castaneum, is one of the most common and economically important pests of stored cereal products worldwide. Furthermore, these beetles can act as vectors for several fungal post-harvest diseases. In this study, we collected T. castaneum from 49 rice processing complexes (RPCs) nationwide during 2016-2017 and identified contaminating fungal species on the surface of the beetles. Five beetles from each region were placed on potato dextrose agar media or Fusarium selection media after wet processing with 100% relative humidity at $27^{\circ}C$ for one week. A total of 142 fungal isolates were thus collected. By sequence analysis of the internal transcribed spacer region, 23 fungal genera including one unidentified taxon were found to be associated with T. castaneum. The genus Aspergillus spp. (28.9%) was the most frequently present, followed by Cladosporium spp. (12.0%), Hyphopichia burtonii (9.2%), Penicillium spp. (8.5%), Mucor spp. (6.3%), Rhizopus spp. (5.6%), Cephaliophora spp. (3.5%), Alternaria alternata (2.8%) and Monascus sp. (2.8%). Less commonly identified were genera Fusarium, Nigrospora, Beauveria, Chaetomium, Coprinellus, Irpex, Lichtheimia, Trichoderma, Byssochlamys, Cochliobolus, Cunninghamella, Mortierella, Polyporales, Rhizomucor and Talaromyces. Among the isolates, two known mycotoxin-producing fungi, Aspergillus flavus and Fusarium spp. were also identified. This result is consistent with previous studies that surveyed fungal and mycotoxin contamination in rice from RPCs. Our study indicates that the storage pest, T. castaneum, would play an important role in spreading fungal contaminants and consequently increasing mycotoxin contamination in stored rice.

• Journal of Food Hygiene and Safety
• /
• v.1 no.2
• /
• pp.133-141
• /
• 1986

Gamma irradiation as a new physical treatment was applied to comparative researches with a conventional chemical fumigant on the microbiologicai and physicochemical qualities of selected agricultural products such as powdered hot pepper soybean paste,. oyste.mushroom powder, carrot flake, and raw sesame. The microorganisms contaminated in the sample, including total bacteria, thermophiles, acid tolerant bacteria, fungi, osmophilic molds and coliforms were sterilized with irradiation doses of 7-10 kGy, while ethylene oxide (E.O) fumigation proved insufficient for the destruction of them. An optimum dose of irradiation was less detrimental than E.O. fumigation to the physicochemical properties of the sample. Sensory evaluation after three months of storage at room temperatures showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as E.O. fumigated samples.

• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.510-519
• /
• 2021

The purpose of this study was to investigate the effect of the microbial reduction and quality maintenance of the physical and chemical pretreatment of Allium monanthum. For physical treatment, handwash, bubble wash and ultrasonication were conducted at 50℃ and 60℃ for 1, 3 and 5 minutes, respectively, and for chemical treatment the sample was immersed in fumaric acid and acetic acid of 1.5% and 2% concentrations for 1, 3 and 5 minutes, respectively. As a result of the microorganism and quality analysis, 3 minutes of bubble wash was the most effective physical pretreatment in reducing fungi although the effect on reducing total viable bacterial was small. Furthermore, 5 minutes of ultrasonication at 60℃ significantly reduced microorganisms, but also resulted in the reduction of the a value of chromaticity, which cause the green color to fade. With chemical pretreatment, it was found that treating with fumaric acid was more effective in reducing the total viable bacteria and fungi than acetic acid. The result shows that 1.5% concentration of fumaric acid is the most effective with 3 minutes of treatment time. The quality of Allium monanthum were compared in the combination of the two most effective microorganism reduction pretreatments: 3 minutes of bubble wash (B3) and 3 minutes in 1.5% fumaric acid (F153). As a result of analyzing the quality characteristics over 9 days of storage at 4℃ after the treatments, it was revealed that the BF treatment is more effective in reducing fungi than the total viable bacteria. The results shows that the BF treatment is more effective in reducing total viable bacteria, whereas the F153 treatment is more effective in reducing fungi. Also, it was found that the 𝚫E value in BF was the lowest, whereas F153 treatment showed the green color faded. The maximum cohesiveness changed more significantly in the green stems than in the roots. On the 9th day of storage, the hardness of the green stem was found to be maintained at the highest level (P<0.05) after F153 treatment, whereas that of the roots decreased (P<0.05) since the 6th day after the bubble wash. Considering the reduction of microorganisms and the quality maintenance of Allium monanthum, the most effective pretreatment methods were 3 minutes in 1.5% fumaric acid for reducing microorganisms and maintaining color and maximum cohesiveness, and the combined process could also be effective if the expiration period is within 3 days.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.33 no.1
• /
• pp.21-29
• /
• 2013

The studies were conducted to investigate real condition of mycotoxin contamination in the fields before harvest and by the storages of rice straw used as roughage in Korea. It was found mycotoxin contamination before harvest of rice straw that the rice plants were detected deoxynivalenol at the initial growth, ochratoxin A and deoxynivalenol at the middle growth, and deoxynivalenol and zearalenone at the harvest periods in the fields. Also, the rice plants were contaminated by various fungi such as Fusarium sp., Fusarium proliferatum, Penicillium sp., Gibberella sp., Gibberella zeae, Mucor circinelloides and Aspergillus oryzae. The levels of fungal contamination were $10^{3-4}$ cfu/g at the initial growth, and $10^{4-5}$ cfu/g at the middle growth and harvest periods. All storage types of rice straw were contaminated with zearalenone, deoxynivalenol and ochratoxins A. The samples of rice straw contaminating mycotoxins were account for 3% in bundle rice straw, and 38% in both types of square rice straw and rice round bale silage, respectively. When 105 samples of rice bale silage were analyzed for mycotoxins depending on the regional area, mycotoxin contamination was found in 46% of total samples in Korea. Regional contaminations of mycotoxins were respectively 48, 33, 40, 50 and 57% of samples in Gyeonggi, Gangwon, Chungcheng, Yeongnam and Honam area. Rice round bale silage was contaminated by three kinds of mycotoxins (zearalenone, deoxynivalenol and ochratoxinsA) in the all of area without Chungcheong area where was contaminated zearalenone and deoxynivalenol. Ochratoxins A, deoxynivalenol and zearalenone were respectively determinated with the average levels of 2.6, 413 and $338{\mu}g/kg$ in rice round bale silage for the overall area, even if it was some difference depending on each regional area. Therefore, the above results clearly show that the rice straws were exposed to the contamination by mycotoxin and mycotoxigenic fungi before harvest in the fields, and mycotoxin contamination was not dependent on the regional area or the storage types such as bundle rice straw, square rice straw and rice round bale silage.

• Korean Journal of Medicinal Crop Science
• /
• v.2 no.3
• /
• pp.211-218
• /
• 1994

This experiment was conducted to obtain basic information for the establishment of in vitro initial culture system in Fritillaria thuubergii Miq. Methods of surface sterilization of scale segments as explant and effect of antibiotics added into the culture medium on contamination of explant and chilling treatment of mother bulb on bulblet formation were investigated. Portent of contamination of cultured scale segments was significantly higher in the outer scale segments which were unsuitable as initial culture explant than inner scale segments. Contamination of explants taken from inner scale of bulb was reduced by surface sterilizing explants in the solution of $4{\sim}5%$ sodium hypoclorite for $10{\sim}15$ mimutes. Addition of antibiotics such as kanamycin, vancomycia cefotaxim, agrirnycin and agreptomycin and dithane as fungicide and$lncyte^{tm}$ into MS medium was effective to reduce bateriological contamination, but did not work to control fungi. It had effective to delay the degree of contamination caused by fungi and bacteria haboring in cultured explants. Bulblet formation from cultured scale segments was promoted by dry storage for $2{\sim}4$ weeks or moisture storage of mother bulbs for $4{\sim}6$ weeks at $10^{\circ}C$ before excision of explants. Addition of kinetin into medium could not exerted for the bulblet formation from the scale segment of dry storaged bulb compared to control. But explant taken from 6 week moisture storaged bulb formed more than 10 bulblets per explant on the medium containing $3{\sim}5mg/L$ kinetin.

• Korean Journal of Food Science and Technology
• /
• v.32 no.3
• /
• pp.640-645
• /
• 2000

The effect of gamma-irradiation on the quality changes of the grain shape improved Meju was studied. Meju was prepared, irradiated at 0, 5, 10 and 20 kGy, and then stored at $25^{\circ}C$ for six months. The results showed that the fungi and acid producing bacteria were completely eliminated by gamma-irradiation with dose of 10 kGy or higher and the Bacillus was decreased by 5 log cycles with dose of 10 kGy. The $D_{10}$ values of the fungi, Bacillus and acid producing bacteria were 0.79, 2.28 and 1.17 kGy, respectively. Also, the microorganisms that survived irradiation was decreased significantly with the duration of storage period. The $NH_3-nitrogen$, negative factors of quality of Meju, and browning were repressed and the protease activity and pH were not affected by gamma-irradiation. Therefore, it was considered that the Meju treated with gamma-irradiation maintained better quality than that of the control with storage.

• Journal of Conservation Science
• /
• v.26 no.4
• /
• pp.429-436
• /
• 2010

Dyestuffs extracted from fifteen kinds of natural dyeing materials were researched on their antimicrobial performance against 3 kinds of bacteria and 2 kinds of fungi in order to develop conservation/storage materials of traditional and natural dyed papers. The three types of mordants were evaluated by using the same method and then mixed with the dyestuffs to research their antimicrobial performance. With those results, dyed paper was made by mixing mordants with 9 kinds of dyestuffs with excellent antimicrobial performance. Among the dyed papers, Cotinus coggygria, Coptis chinensis, Phellodendri amurense, Rhus javanica and Acer ginnala multiple mordant papers were found to have an antibacterial quality against fungi, while, in the insect repellent experiment using termites, Coptis chinensis and Phellodendri amurense dyed papers were found to have insect repellent qualities. Also, with regard to the research result about the affect of dyeing paper on other materials like metal, Coptis chinensis have relatively stable qualities. Also, the three types of dyeed paper by Cotinus coggygria, Coptis chinensis and Phellodendri amurense, were found to have a tendency to remove harmful gases. Not only can these dyed papers be used for making storage box for cultural properties to prevent various organic artifacts from bio-damaging, but they can also be utilized as functional finishing materials in various spaces.

• Korean Journal of Food Science and Technology
• /
• v.26 no.6
• /
• pp.814-818
• /
• 1994

Control system for both rapid fermentation and storage of yogurt in refrigerator was developed and its performance was investigated. Fermentation temperature for normal and Bifidus containing yogurt was maintained at maximum $40^{\circ}C$ for about 7 and 11 hours, respectively. The pH, acidity, total viable cell number of lactic acid bacteria and viscosity of both yogurts after completing the fermentation were $4.23{\sim}4.29$, $0.93{\sim}0.97%$, $4.8{\times}10^7{\sim}$2.54{\times}10^8\;cfu/ml$ and $1,700{\sim}1,810\;cp$, respectively. The rate of fermentation for normal yogurt was faster than that of Bifidus yogurt. The changes of pH, acidity, viable cell number and viscosity during storage time were $4.09{\sim}4.54$, $0.76{\sim}1.1%$, $9.4{\times}10^6{\sim}5.68{\times}10^8\;cfu/ml$ and $1,450{\sim}2,000\;cp$, respectively. Yeast and fungi were not nearly detected during storage time for both yogurts.

• Korean Journal of Food Science and Technology
• /
• v.26 no.3
• /
• pp.300-304
• /
• 1994

To predict quality change of Kochujang distributed in the market, physicochemical properties were observed during storage at $13^{\circ}C$, $27^{\circ}C$ and $37^{\circ}C$ for 240 days. Moisture, crude protein and capsaicin contents were nearly constant for storage at the selected temperatures. Amino nitrogen, value of surface color and pH were decreased during storage while ammonia nitrogen and titratable acidity were increased. Storage temperature affected quality change significantly as higher temperature showed clear increase or decrease phenomena of above factors. Number of total cell count was not changed significantly, and fungi was not detected. From the correlation coefficient among physicochemical properties and sensory evaluation scores, the highest correlation was obtained in amino nitrogen content and sensory score. Degradation of amino nitrogen was a first order reaction, and the $Q_{10}$ value calculated from reaction constant was 2.98. Also, activation energy for the destruction of amino nitrogen calculated from Arrhenius equation was 15.34 Kcal/mole.