• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.49-54
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• 1988

The present experiment was conducted to investigate causes affecting the reduction of red pepper production in the continuous cultivation upland soil from 1985 to 1986 in Imsil Chonbuk Province. The results obstained are summarized as follows: 1. Area ratio of continuous cultivation 2 years was 12.7%, 3 years 6.8% and over 4 years 48.9%. 2. Soil hardness and volume of solid and liguid of red pepper continuous cultivation soil were higher than those of one year cultivation, while pH and content of organic matter of continuous cultivation soil were low. The exceeding optimum level of phosphorus and potassium appeared factors affecting and reduction of red pepper of continuous cultivation soil. 3. Microflora density in continuous cultivation soil was high but bacteria/fungi (B/F) and actinomycetes/fungi (A/F) ratio were low. 4. The density of soil nematodes in continuous cultivation soil were higher than that in one year cultivation soil, however, the steeper and better drainage soil lowered the density of nematodes. 5. Continuous cultivation over 4 years showed 14.3% of plants diseased by phytophthora while 0.7% in one year cultivation soil.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.167-174
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• 2000

To investigate the effect of amount of nitrogen application on decomposition of barley straw, growth and yield of rice in paddy field of double cropping, this study was conducted to Jeonbuk series at the Honam area from 1997 to 1998. Carbon persistence of barley straw was lowered while nitrogen persistence rate was increased as increasing amount of nitrogen application and carbon -nitrogen ratio was not decreased as increasing amount of nitrogen application. Soil microflora under barley straw application was high in order of actinomycetes>cellulosedecomposer>bacteria>fungi. Nitrogen starvation under barley straw application showed at tillering stage of rice, but this was not appeared in plot of N $144kg\;ha^{-1}$ application. Plant height, culm length and ear length of rice plant by barley straw application were short, but those of N $108kg\;ha^{-1}$ application was not different from compared with none-application barley straw. Rice yield of N $108kg\;ha^{-1}$ applied barley straw was smiliar to none-application barley straw, but that of N 90. $144kg\;ha^{-1}$ was highly decreased.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.382-391
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• 2021

The purpose of this study was to investigate the microbial contamination of red pepper powder distributed within Gyeonggi province in 2020 according to the place of purchase, the country of origin, and whether the HACCP certification and sterilization were conducted, and to evaluate the change of quality according to the storage method. Upon collecting and analyzing 100 samples, Bacillus cereus was detected in 3 cases (2 cases in large supermarkets and 1 case in traditional markets) and Clostridium perfringens in 27 cases (9 cases in large supermarkets and 18 cases in traditional markets). The levels of the total aerobic bacteria were not significantly different between the red pepper powder purchased from large supermarkets and traditional markets. However, the frequency of red pepper powder exceeding 7 log CFU/g of total aerobic bacteria was higher in traditional markets than in large supermarkets. Microbial quality was not significantly different regardless of the storage temperature (30℃, 4℃, -20℃) and the packaging method (zipper bag and clean bag) after 7 months of purchase. However, the moisture contents and ASTA color value of red pepper powder stored at 30℃ decreased remarkably after 3 months of storage. It is desirable to store red pepper powder in a refrigerator or freezer in order to maintain its quality during long-term storage.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.218-222
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• 2021

This study aimed to investigate bacterial disinfection in drinking water using a water purifier. Water artificially inoculated with Escherichia coli and Listeria monocytogenes at various concentrations was irradiated using ultraviolet (UV)-C at a rate of 3.4 L/min in a water purifier, and the disinfection effects of UV-C were evaluated. Both E. coli and L. monocytogenes were disinfected up to 107 colony-forming units (CFU)/2.8 L by the UV-C irradiation. Additionally, morphological study using fluorescence microscopy in conjunction with live/dead staining revealed that both the bacteria species were disinfected by the UV-C irradiation. Therefore, UV-C in water purifiers can effectively kill high concentrations of bacteria in distilled water. UV irradiation (UV-C: 254 nm wavelength, irradiation dose: 40 mJ/㎠) at a flow rate of 3.4 L/min on drinking water has the potential to sterilize bacteria-contaminated drinking water, at least for 3.2×107 CFU/2.8 L of E. coli and 8.4×107 CFU/2.8 L of L. monocytogenes.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.248-259
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• 2021

BACKGROUND: Contaminated water was a major source of food-borne pathogens in various recent fresh produce-related outbreaks. This study was conducted to investigate the microbial contamination level and correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water by logistic regression analysis. METHODS AND RESULTS: Agricultural water was collected from 457 sites including surface water (n=300 sites) and groundwater (n=157 sites) in South Korea from 2018 to 2020. Sanitary indicator bacteria (total coliform, fecal coliform, and Escherichia coli) and food-borne pathogens (pathogenic E. coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were analyzed. In surface water, the coliform, fecal coliform, and E. coli were 3.27±0.89 log CFU/100 mL, 1.90±1.19 log CFU/100 mL, and 1.39±1.26 log CFU/100 mL, respectively. For groundwater, three kinds of sanitary indicators ranged in the level from 0.09 - 0.57 log CFU/100 mL. Pathogenic E. coli, Salmonella and Listeria monocytogenes were detected from 3%-site, 1.5%- site, and 0.6%-site water samples, respectively. According to the results of correlations between the level of sanitary indicator bacteria and the detection ratio of pathogens by logistic regression analysis, the probability of pathogen detection increased individually by 1.45 and 1.34 times as each total coliform and E. coli concentration increased by 1 log CFU/100mL. The accuracy of the model was 70.4%, and sensitivity and specificity were 81.5% and 51.7%, respectively. CONCLUSION(S): The results indicate the need to manage the microbial risk of agricultural water to enhance the safety of fresh produce. In addition, logistic regression analysis is useful to analyze the correlation between the level of sanitary indicator bacteria and the detection ratio of pathogens in agricultural water.

• Food Engineering Progress
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• v.13 no.1
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• pp.64-69
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• 2009

From the 25 fresh fruits and vegetable products, 1,250 isolates grown on MRS agar media were screened for the inhibitory activity on the growth of Escherichia coli 0157:H7, Listeria monocytogenes, and Bacillus cereus as well as Lactobacillus plantarum, L. casei, and Lactococcus lactis subsp. lactis. Among them, 607 isolates (49% of total isolates) from 23 different foods produced growth inhibitory activity on the E. coli 0157:H7, L. monocytogenes, or B. cereus. When these isolates were screened for the inhibitory activity on the growth of L. plantarum, L. casei, and Lactococcus lactis subsp., 24 isolates (3% of total isolates) from 7 food samples showed bacteriocin-like activity. These isolates had typical physiological characteristics of lactic acid bacteria, which indicated these isolates were strains of lactic acid bacteria. The inhibitor from 3 out of 24 revealed as nicin. From the RAPD-PCR profiles, 24 strains was classified and it was also indicated that most of the strains isolated from same produce showed similar phylogenetic profile.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.534-538
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• 2009

Japanese apricot (Prunus mume) "Okboseok" was released from a cross between "Nanko" and "Yoseibai" in 1993 at the Pear Research Station of National Institute of Horticultural and Herbal Science, Rural Development Administration. It was preliminarily selected in 2001 and named in 2006. It produces high yield with a flesh about average 88.3% of fruit, although the fruit size is small (approximately 14.0g). Horticultural and physiological harvest time of this cultivar is mid and late June respectively. It has single flowers with pink petal color and its flowering time is about 4 days later than that of "Nanko". Its fruit is tolerant to bacterial shot hole (Xanthomonas arboricola pv. Pruni) and pear scab (Venturia nashicola). "Okboseok" has abundant pollen grains (about 96 mg/100 flowers), thus it could be a pollinizer. To obtain stable yields, however, its compatibility with major cultivars is needed to be confirmed as pollinizer cultivar. "Okboseok" is recommended for being preserved in sugar and liquor.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.665-670
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• 2018

This study was designed to evaluate the physicochemical properties and biological activities (antioxidant activity and antimicrobial activities) of three and seven-year-old Platycodon grandiflorum extracts. Three and seven-year-old Platycodon grandiflorum contained crude saponins, free amino acids and minerals. Water extracts of the three and seven-year-old plants were prepared using reflux extraction methods. The total polyphenol contents (TPC), total flavonoid contents (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity and antimicrobial effects of the extracts were determined. The seven-year-old Platycodon grandiflorum extract had higher TPC ($5.08{\pm}0.07TAEmg/g$) and TFC ($3.80{\pm}0.07QUEmg/g$). DPPH radical scavenging activity ($IC_{50}$ value: $288{\pm}3.88{\mu}g/mL$) and ABTS radical scavenging activity ($IC_{50}$ value: $568{\pm}2.09{\mu}g/mL$). The three and seven-year-old Platycodon grandiflorum extracts exhibited a strong antimicrobial effect against three kinds of bronchus disease-inducing bacteria; the seven-year-old Platycodon grandiflorum extracts showed a stronger antimicrobial effect than the three-year-old Platycodon grandiflorum extracts.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.131-142
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• 2019

The primary objective of this study was to determine the content of biogenic amines in Korean traditional fermented soybean pastes (doenjang) and to isolate potential probiotic Bacillus sp. with the ability to inhibit biogenic amines accumulation. There were significant differences in the bacterial cell counts, pH value, titratable acidity, salinity, and biogenic amine content between the samples. Among Bacillus strains isolated from doenjang, Bacillus (B.) licheniformis DB102, B. subtilis DB203, B. stearothermophilus DB206, Bacillus sp. DB209, Bacillus sp. DB310, B. coagulans DB311, B. cereus DB313, B. amyloliquefaciens DB714, Bacillus sp. DB917, B. cereus DB 915, B. subtilis DB1020, and Bacillus sp. DB1022 were found to be able to produce biogenic amines. On the other hand, biogenic amine-degrading strains were identified as Bacillus sp. DB403, Bacillus sp. DB407, B. subtilis DB517, B. licheniformis DB612, and B. subtilis DB821. In particular, Bacillus sp. DB407 and B. subtilis DB821 showed probiotic properties including tolerance to artificial digestive juices, adherence to intestinal epithelial cells, resistance to antibiotics, and antibacterial activity against biogenic amine-producing strains. In conclusion, the two probiotic Bacillus strains may be considered as the suitable starter for manufacture of fermented soybean foods with low biogenic amines content.

• Journal of Mushroom
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• v.16 no.4
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• pp.257-262
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• 2018

The aim of this study was to re-use spent mushroom substrate (SMS) with increased total nitrogen (T-N) and amino acid content and reduce the amount of cottonseed meal used as nutrient supplement in Pleurotus ostreatus cultivation. Bacteria used for improvement of the T-N content were GM20-4(Bacillus sp.) and Rhodobacter sphaeroides (RS). GM20-4 was isolated from the SMS of P. ostreatus and RS was obtained from Gwangjusi agricultural technology center. SMS in T1, T2, and T3 was reused as substrate after drying and the T-N content of dried SMS (D-SMS) was increased by 0.34% by treatment with the bacteria. T1 with 8% D-SMS and T2 with 18% D-SMS had higher rates of primordia formation compared with T3 and the control. The biological efficiency of the control and of treatment with 8%, 18%, and 26% D-SMS was 110%, 114%, 112%, and 79%, respectively. Considering the economic cost, yield, and biological efficiency, T2 with 18% D-SMS as the culture substrate for P. ostreatus was shown to be the most effective for cultivation.