• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.117-126
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• 2012

This study was conducted to assess the levels of microbiological hazards of preprocessed Namuls, which were served at the school foodservice. 19 preprocessed ground or root vegetables were collected from 21 schools in May to June of 2011. Heavy contamination of aerobic plate counts (from 3.39 to 8.42 logCFU/g) and total coliform groups (from 3.16 to 7.84 logCFU/g), enterobacteriaceaes (from 2.53 to 7.55 logCFU/g) were detected in preprocessed Namuls. In addition, the detection rates of Escherichia coli, Staphylococcus aureus and Bacillus cereus (emetic form) were 4.3%, 11.7% and 2.1%, respectively. In addition, sanitary indicative bacterium at preprocessing steps of root vegetables (lotus root, burdock root, bellflower root) and blanched Namuls (bracken, sweet potato vine, chinamul) were analyzed. Aerobic plate counts, coliform groups, and enterobacteriaceaes were not effectively removed during preprocessing including washing and soaking steps. In the case of blanched Namuls (bracken, sweet potato vine, chinamul), contamination levels increased more after drying process and no significant reduction effect on the levels of microbial contamination was observed during preprocessing steps. Thus, effect of preprocessing steps on the microbiological hazards in Namuls must be reevaluated to improve the microbiological quality of preprocessed Namuls at the school foodservice and retail markets.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.109-116
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• 2012

The study indicated that antimicrobial activity about gram positive and gram negative bacteria of ginger-oleoresin(GO) extract with the condition of ethanol and supercritical fluid extractions. As the concentration of extraction increases, the clear zone of GO ethanol extract also increased dependently. This led the antimicrobial activity of gram positive bacteria to take bigger place than gram negative bacteria especially in Listeria monocytogenes. There was a high antimicrobial activity in E-III treatment where the ratio of the ginger powder extract to ethanol extraction was 1:6. It was quite effective to treat the antimicrobial activity of GO ethanol extract under $80^{\circ}C$ and there was not big difference in the intervals which were the extraction time - 1 to 7 hours. The antimicrobial activity of supercritical fluid extract seemed to take the biggest place in Listeria monocytogenes. From the supercritical fluid extract, it was shown the strong ability of antimicrobial activity in the condition with 100 bar $35^{\circ}C$, 250 bar $35^{\circ}C$ and 250 bar $65^{\circ}C$. Furthermore, according to the case of solvent extract, there was not any significant difference in the antimicrobial activity with condition of extraction. However, there was significant antimicrobial activity in E-III treatment of 100 bar and 500 bar of extraction pressure, and $35^{\circ}C$ and $65^{\circ}C$ of extraction temperature.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.39-43
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• 2014

The antimicrobial activity of Orixa japonica Thunb. leaf extract towards 13 microorganism strains was evaluated. Both methanol (MEex) and 70% ethanol extracts showed antimicrobial activity towards Streptococcus mutans, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa. MEex showed a higher antimicrobial activity than the 70% ethanol extract. In addition, the dichloromethane fraction (DCMfr) of the MEex also had an antimicrobial effect against the microorganisms examined. The minimum inhibitory concentrations (MICs) towards S. mutans, B. cereus, S. aureus, and P. aeruginosa were 49.22, 24.61, 49.22, and 49.22 mg/mL, respectively. In contrast, the MICs of the DCMfr tpwards S. mutans, B. cereus, S. aureus, and P. aeruginosa were 3.31, 0.21, 1.7, and 1.7 mg/mL, respectively. The MEex antimicrobial activity was not affected by a 3 h exposures to pH in the range of 3-11 or by temperatures were maintained between $80^{\circ}C-100^{\circ}C$ for 6 h. However, the MEex antimicrobial activity decreased at a heat treatment of $121^{\circ}C$ 1 h.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.20-27
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• 2017

Eighteen commercial laver (Porphyra sp.) products were purchased from Korean market and were monitored for their microbial contamination, pre-decontamination, and luminescence properties. The laver samples showed considerable variation in their microbial contamination, from $10-10^7CFU/g$ of total aerobic counts, <$10-10^2CFU/g$ of coliforms in 4 dried laver samples, and <$10-10^6CFU/g$ of yeasts and molds except in 3 samples. In addition, $10^2CFU/g$ of Bacillus cereus was found in one sample. DEFT/APC analysis was suitable for demonstrating whether the samples were pre-decontaminated or not, with DEFT/APC values lower than 2.0 log for non-heated samples and 1.0-8.5 log for heatprocessed samples. In photostimulated luminescence (PSL) calibration, 15 samples irradiated at 1 kGy showed positive (irradiated) values more than 5000 PCs. Furthermore, thermoluminescence (TL) analysis by separating the marker minerals from samples revealed the potential to be employed in identifying irradiation status by determining $1^{st}$ TL glow at $125-175^{\circ}C$ and TL ratio ($TL_1/TL_2$) of all the samples.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.140-145
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• 2000

This study was performed to investigate whether the earthworm cast could be reused as bulking agent in the whole processing of the food wastes using the earthworm. In addition, the growth conditions of microorganism lived upon earthworm lasts was investigated. Because the raw food wastes used in this experiment had low pH, and high moisture and organic matter contents, it was unsuitable to use as direct feeds to earthworm. However, when the food wastes were mixed with some earthworm cast, the mixtures were suitable to the feed condition and the growth environment of the earthworm. Therefore, it shows the possibility that the earthworm cast be reused as bulking agent for food wastes. In the microbiological investigation on earthworm cast, the bacteria showed most high density among the microbial species. And the microbial density showed higher under the mid-temperature than under high-temperature, and higher under the anaerobic than the aerobic condition. The drying methods of earthworm cast for the moisture adjusting, has no effect on microorganism growth whether natural or artificial drying. And the activity of enzyme presented more highly before the drying than after the drying.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1269-1275
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• 2006

The selection of multienzyme complex-producing bacteria under aerobic condition was conducted for improving the degradation of lignocellulosic substances. The criteria for selection were cellulase and xylanase enzyme production, the presence of cellulose-binding domains and/or xylan-binding domains in enzymes to bind to insoluble substances, the adhesion of bacterial cells to insoluble substances, and the production of multiple cellulases and xylanases in a form of a high molecular weight complex. Among the six Bacillus strains, isolated from various sources and deposited in our laboratory, Paenibacillus curdlanolyticus B-6 strain was the best producer of cellulase and xylanase enzymes, which have both cellulose-binding factors (CBFs) and xylan-binding factors (XBFs). Moreover, multiple carboxymethyl cellulases (CMCases) and xylanases were produced by the strain B-6. The zymograms analysis showed at least 9 types of xylanases and 6 types of CMCases associated in a protein band of xylanase and cellulase with high molecular weight. These cells also enabled to adhere to both avicel and insoluble xylan, which were analyzed by scanning electron microscopy. The results indicated that the strain B-6 produced the multienzyme complex, which may be cellulosome or xylanosome. Thus, P. curdlanolyticus B-6 was selected to study the role and interaction between the enzymes and their substrates and the cooperation of multiple enzymes to enhance the hydrolysis due to the complex structure for efficient cellulases and xylanases degradation of insoluble polysaccharides.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1087-1093
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• 2005

The population diversity and seasonal changes of bacterial communities in rice soils were monitored using both culture-dependent approaches and molecular methods. The rice field plot consisted of twelve subplots planted with two genetically-modified (GM) rice and two non-GM rice plants in three replicates. The DGGE analysis revealed that the bacterial community structures of the twelve subplot soils were quite similar to each other in a given month, indicating that there were no significant differences in the structure of the soil microbial populations between GM rice and non-GM rice during the experiment. However, the DGGE profiles of June soil after a sudden flooding were quite different from those of the other months. The June profiles exhibited a few intense DNA bands, compared with the others, indicating that flooding of rice field stimulated selective growth of some indigenous microorganisms. Phylogenetic analysis of l6S rDNA sequences from cultivated isolates showed that, while the isolates obtained from April soil before flooding were relatively evenly distributed among diverse genera such as Arthrobacter, Streptomyces, Terrabacter, and Bacillus/Paenibacillus, those from June soil after flooding mostly belonged to the Arthrobacter species. Phylogenetic analysis of 16S rDNA sequences obtained from the soil by cloning showed that April, August, and October had more diverse microorganisms than June. The results of this study indicated that flooding of rice fields gave a significant impact on the indigenous microbial community structure; however, the initial structure was gradually recovered over time after a sudden flooding.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.493-502
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• 2009

The concentrations of outdoor airborne bacteria measured in Seoul, Korea for one year (Jan. 2008~Dec. 2008) ranged from $500CFU/m^3$ to $7,500CFU/m^3$. In monthly concentration distribution, the level of outdoor airborne bacteria was highest in September and October and lowest in March. In seasonal concentration distribution, the order of level of outdoor airborne bacteria was autumn>winter>spring>summer. In regional concentration distribution, the highest level of outdoor airborne bacteria was generally found in the forest, followed by general area and traffic site. In distribution characteristics according to particle size, outdoor airborne bacteria showed 31% for >$7.0{\mu}m$ (stage 1), 21% for $4.7{\sim}7.0{\mu}m$(stage 2), 15% for $3.3{\sim}4.7{\mu}m$(stage 3), 19% for $2.1{\sim}3.3{\mu}m$(stage 4), 10% for $1.1{\sim}2.1{\mu}m$(stage 5), and 4% for $0.65{\sim}1.1{\mu}m$(stage 6) and its mean respirable fraction was 48%. In concentration distribution by yellow dust, the mean levels of outdoor airborne bacteria were 803 $(\pm479)CFU/m^3$ for period of yellow dust and 691 $(\pm1,134)CFU/m^3$ for period of non-yellow dust. Although the level of outdoor airborne bacteria was higher in period of yellow dust than period of non-yellow dust, there was no significant difference between period of yellow dust and non-yellow dust (p>0.05). In correlation analysis between outdoor airborne bacteria and atmospheric factors (temperature and relative humidity), there was no significant correlation between outdoor airborne bacteria and atmospheric factors. The predominant airborne bacteria were identified to the Bacillus-derived species.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.656-660
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• 2013

Pseudomonas fluorescens strain CL0145A was discovered at the New York State Museum Field Research Laboratory as an effective agent against the environmentally destructive zebra mussel, which has contaminated US waters. Dried cells of the microbe are being commercialized as an environmentally friendly solution to the problem. We found that antibiotic activity against the Gram-positive bacterium Bacillus subtilis is produced and excreted by this strain. We have carried out studies to optimize production of the antibiotic. Studies were begun in a complex corn meal medium. Activity was found in both cells and culture supernates and was maximal after one day of fermentation. Static fermentation conditions were found to be superior to shaken culture. Production of extracellular antibiotic in complex medium was found to be dependent on the content of sucrose and enzyme-hydrolyzed casein. Indeed, production was greater in sucrose plus enzyme-hydrolyzed casein than in the complex medium. Of a large number of carbon sources studied as improvements over sucrose, the best was glycerol. An examination of nitrogen sources showed that production was improved by replacement of enzyme-hydrolyzed casein with soy hydrolysates. Production in the simple glycerol-Hy-Soy medium was not improved by addition of an inorganic salt mixture or by complex nitrogen sources, with the exception of malt extract. In an attempt to keep the medium more defined, we studied the effect of amino acids and vitamins as replacements for malt extract. Of 21 amino acids and 7 vitamins, we found tryptophan, glutamine, biotin, and riboflavin to be stimulatory. The final medium contained glycerol, Hy-Soy, tryptophan, glutamine, biotin, and riboflavin.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.69-74
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• 2002

This study was conducted to investigate the milk quality produced from dairy farms in Jeju province and to analyze the variety of pathogenes and the number of somatic cells in the milk. Data were collected from 262 lactating cows from 8 farms of three regions and the results obtained are summarized as follows. 1. The average daily milk yields and milk fat contents from June and October were 22.3 kg and 3.7%, respectively. 2. The average number of bacterial counts in raw milk was 1.5${\times}10^4$/ml, but that in farm A was over 3.0${\times}10^4$/ml. 3. The somatic cell counts were 2.5${\times}10^5$/ml in average and those in farm G and H were higher than those in other farms. Their distribution in 262 lactating cows from June to October was as follows; less than 2.0${\times}10^4$ /ml in 68.8% of cows, 2.0-5.0${\times}10^4$/ml in 18.8% of cows and more than 5.0${\times}10^4$/ml in 12.4% of cows. 4. Of the 113 isolates (compartments of cow udder) from mastitic milk, Staphylococcus aureus was found in 47, Streptococcus ogalatiae in 17 and Bacillus in 12. 5. The average monthly income of the farmers was 407 thousand won/head, and that in farm A or E was higher than that of farm H (456-475 thousand won vs. 314 thousand won) In conclusion, to improve income dairy farmers should reduce the somatic cell counts in the milk and mastitis infection through regular disinfection and inspection.