• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.227-233
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• 2013

In this study, we evaluated the ability of various disinfectants to suppress the growth of microorganisms in fresh-cut products and organic vegetable. The growth of more than 50% of B. cereus isolates were suppressed by 50% ethanol, 0.1% hydrogen peroxide, 0.4% sodium hypochlorite or 1% calcium oxide. E. coli generally showed high susceptibility to concentration of 10% ethanol, 0.4% sodium hypochlorite and 1% calcium oxide. Eighty percent or more of S. aureus isolates exhibited resistance to ethanol, hydrogen peroxide and sodium hypochlorite, but the isolates were susceptible to concentrations of 1% calcium oxide. All isolates evaluated in this study were sensitive to benzalkonium chloride (BAC) and growth in the presence of $2.0{\mu}g/mL$ of BAC was completely inhibited. These pathogens showed widely different susceptibilities to different organic acids. Greater than 0.5% acetic acid and 2% and higher concentrations of malic acid and tartaric acid inhibited the growth of 60% of the isolates of B. cereus. Two percent acetic acid and tartaric acid inhibited 50% of the S. aureus isolates. Seventy percent of the E. coli isolates were resistant to malic acid and susceptible to 1% acetic acid and 10% tartaric acid. The antibacterial effects of the various sanitizers evaluated in this study were not only dependent on the type of disinfectant but also on the pathogen. Thus, it is important to select a sanitizer that is safe and effective at removing specific types of microorganisms.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.243-248
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• 2017

Intracellular and extracellular oxidative stress initiated by reactive oxygen species (ROS) causes skin aging, which is characterized by wrinkles and atypical pigmentation. Use of antioxidant is an effective approach to prevent symptoms related to ROS-induced aging of the skin. Therefore, the antioxidant and anti-aging effect of Castanea crenata Siebold & Zucc. extracts (LCE) was investigated in this study. The LCE markedly reduced the hydrogen peroxide-induced cell damage, intracellular ROS, and oxidative stress-induced senescence in human dermal fibroblasts (HDFs). These results indicate that LCE might have beneficial effects on oxidative stress-induced damage and thus reduce skin aging.

• Composites Research
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• v.36 no.4
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• pp.246-252
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• 2023

A secondary barrier made of glass fiber reinforced composites has been installed infinitely using automatic bonding machine(ABM) in membrane type LNG cargo containment system (CCS). At the same time, significant thermal stress due to cryogenic heat shrinkage has occurred in the composite on the non-bonding area between the adhesive fixation at both ends. There have been studies from the perspective of structural safety evaluation taking this into account, but none that have analyzed mechanical property taking an prolonged length into account. In this study, 2-parameter Weibull distribution statistical analysis was used to standardize reliable mechanical property for actual length, taking into account the composite's brittle fracture of ceramic material with wide fracture strength dispersion. Related experimental data were obtained by performing uniaxial tensile tests at specific temperatures below cryogenic condition considering LNG environment. As a result, the mechanical strength increased about 1.5 times compared to -20℃ at -70℃ and initial non-linear behavior of fiber stretched was suppressed. As the temperature decreased until the cryogenic, the mechanical strength continued to increase due to cold brittleness. The suggested mechanical property in this study would be employed to secure reliable analysis support material property when assessing the safety of secondary barrier's structures.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1318-1322
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• 2008

The aim of this study was to analyze the antioxidant properties of Lycii folium extracts prepared from different solvents. Lycii folium were extracted with water, 80% ethanol (80% EtOH), 80% methanol (80% MeOH) and 100% methanol (100% MeOH) in water bath at $40^{\circ}C$. The antioxidant activity of the extracts was evaluated using DPPH, hydroxyl and hydrogen radical scavenging activities, and SOD-liked activity. Total phenolic acid contents were 1.085 mg/mL in 100% MeOH, 1.382 mg/mL in 80% EtOH, 1.420 mg/mL in 80% MeOH and 1.084 mg/mL in water. DPPH radical scavenging activity of the extracts were 65.60% in 80% EtOH, 56.80% in 80% MeOH, 83.85% in 100% MeOH and 54.65% in water. Hydroxyl radical scavenging activities were 66.65% in 100% MeOH, 73.13% in 80% ethanol, 73.58% in 80% MeOH and 70.73% in water. Hydrogen radical scavenging activity of the extracts prepared from Lycii folium were 11.70% in 100% MeOH, 33.73% in 80% EtOH, 35.40% in 80% M eOH and 23.86% in water. SOD-liked activity of the extracts prepared from Lycii folium was 71.58% in 100% MeOH, 74.29% in 80% EtOH, 88.46% in 80% MeOH and 67.47% in water. Our result showed that Lycii folium extracts prepared from 80% methanol were found to be promising biomaterials with antioxidant effects.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.285-294
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• 2011

The abatement of methane emission from ruminants is an important global issue due to its contribution to greenhouse gas with carbon dioxide. Methane is generated in the rumen by methanogens (archaea) that utilize metabolic hydrogen ($H_2$) to reduce carbon dioxide, and is a significant electron sink in the rumen ecosystem. Therefore, the competition for hydrogen used for methanogenesis with alternative reductions of rumen microbes should be an effective option to reduce rumen methanogenesis. Some methanogens parasitically survive on the surface of ciliate protozoa, so that defaunation or decrease in protozoa number might contribute to abate methanogenesis. The most important issue for mitigation of rumen methanogenesis with manipulators is to secure safety for animals and their products and the environment. In this respect, prophylactic effects of probiotics, prebiotics and miscellaneous compounds to mitigate rumen methanogenesis have been developed instead of antibiotics, ionophores such as monensin, and lasalocid in Japan. Nitrate suppresses rumen methanogenesis by its reducing reaction in the rumen. However, excess intake of nitrate causes intoxication due to nitrite accumulation, which induces methemoglobinemia. The nitrite accumulation is attributed to a relatively higher rate of nitrate reduction to nitrite than nitrite to ammonia via nitroxyl and hydroxylamine. The in vitro and in vivo trials have been conducted to clarify the prophylactic effects of L-cysteine, some strains of lactic acid bacteria and yeast and/or ${\beta}$1-4 galactooligosaccharide on nitrate-nitrite intoxication and methanogenesis. The administration of nitrate with ${\beta}$1-4 galacto-oligosaccharide, Candida kefyr, and Lactococcus lactis subsp. lactis were suggested to possibly control rumen methanogenesis and prevent nitrite formation in the rumen. For prebiotics, nisin which is a bacteriocin produced by Lactococcus lactis subsp. lactis has been demonstrated to abate rumen methanogenesis in the same manner as monensin. A protein resistant anti-microbe (PRA) has been isolated from Lactobacillus plantarum as a manipulator to mitigate rumen methanogenesis. Recently, hydrogen peroxide was identified as a part of the manipulating effect of PRA on rumen methanogenesis. The suppressing effects of secondary metabolites from plants such as saponin and tannin on rumen methanogenesis have been examined. Especially, yucca schidigera extract, sarsaponin (steroidal glycosides), can suppress rumen methanogenesis thereby improving protein utilization efficiency. The cashew nutshell liquid (CNSL), or cashew shell oil, which is a natural resin found in the honeycomb structure of the cashew nutshell has been found to mitigate rumen methanogenesis. In an attempt to seek manipulators in the section on methane belching from ruminants, the arrangement of an inventory of mitigation technologies available for the Clean Development Mechanism (CDM) and Joint Implementation (JI) in the Kyoto mechanism has been advancing to target ruminant livestock in Asian and Pacific regions.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.712-716
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• 2008

In an effort to evaluate Salmonella food safety using combinations of preservation techniques, its viabilities when exposed to HCl, acetic acid, and the oxidative agents (hydrogen peroxide and butyl hydrogen peroxide), were analyzed using sub-lethal heat-shocked Salmonella Typhimurium at $56^{\circ}C$. 2D gel electrophoresis and MALDI-TOF MS analyses were also conducted to determine the expression and repression of proteins in heat-shocked cells. Heat-shocked S. Typhimurium evidenced a reduction of viable counts by 1-2 log CFU/mL. However, viality of non heat-shocked S. Typhimurium decreased markedly by 5-6 log CFU/mL at a pH 4 in response to acid and oxidative stresses. Sub-lethal heat treatment greatly increased the resistance of S. Typhimurium against acid and oxidant agents. As for 2D gel electrophoresis and protein identification via MALDI-TOF MS, 17 major proteins in non heat-shocked S. Typhimurium were detected, and only 13 proteins among these proteins were detected in heat-shocked S. Typhimurium. The heat shock proteins such as DnaK and small heat shock proteins were included, and may be associated with the resistance of S. typhimurium against exposure to acids and oxidants. Therefore, even though the promising hurdle technology using the combined mild treatments including heat was applied to S. Typhimurium, the proper heat treatment to reduce its crossprotection activity toward the following preservative agents might be considered.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.875-879
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• 2005

Linustatin and neolinustatin in flaxseed are called cyanogenic glucosides which produce acetone, hydrogen cyanide (HCN) and sugar when hydrolyzed. The HCN is the chemical whose toxin is being issued in food safety. Linustatin and neolinustatin were found in flaxseed by 206.5 and 174.2 mg/100 g, respectively using a RI-HPLC and LC/MSn analysis of $80\%$ methanol extraction. Also, HCN (137.38 mg/kg) was found in flaxseed distillate by autohydrolysis and IC analysis. More than 85$\%$ of linustatin, neolinustatin and HCN were removed when flaxseed was heated for more than 2 hours in $200^{\circ}C$. Especially, HCN was decreased to $98\%$ by heating only 30 min in $200^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.19 no.5
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• pp.69-74
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• 2015

The study investigated numerically the heat transfer and chemical reaction characteristics of a methane-steam reforming by using a 3-dimensional computational fluid dynamics (CFD) code (Fluent ver. 16.1). The fuel temperature and its species mole fractions were estimated for various Reynolds number in the reformer tube at different burner temperatures. The catalysts were modeled as the porous medium of nicrome in the reformer tube. We considered radiation effect as well as conduction and convective heat transfer because the methane-steam was reformed at very high temperature condition above 1000 K. For two different Reynolds numbers of 49,000 and 88,000 and the burner temperatures were in the range from 1,100 K to 1,300 K. At a low Reynolds number, the fuel temperature increased, leading to increase in hydrogen reforming. However, fuel temperature and hydrogen reforming decreased because of higher convective heat transfer from relatively low fuel temperature. Moreover, the hydrogen reforming also increased with burner temperature.

• Korean Journal of Food Science and Technology
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• v.44 no.4
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• pp.401-410
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• 2012

This study examines the authenticity discrimination of the circulated honey by using stable isotope ratio methods. In the case of domestic honey, the range of ${\delta}^{13}C$ for the samples labeled as pure honey was about -27- -21‰ at the $C_3$ origin, and the range of that for artificial honey was over -19‰ at the $C_4$ origin. The range of ${\delta}^{13}C$ for all imported honey was over -27- -23‰ originating from the $C_3$ plant. According to the nectar-source, ${\delta}^2H$ and ${\delta}^{18}O$ for domestic honey were significantly different for 6 and 5 groups, respectively. However, we could not explain the detailed relationship as well as the geographical feature of ${\delta}^2H$ and ${\delta}^{18}O$. The difference for ${\delta}^2H$ and ${\delta}^{18}O$ in the wide range of latitude, such as between Australia and Canada, was more or less shown. However, it was difficult to find out the trends of ${\delta}^2H$ and ${\delta}^{18}O$ for imported honey versus the geographical information in the similar latitudinal country.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.430-437
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• 2016

Objectives: The new Chemical Control Act from the Korean Ministry of Environment (2014-259) simply states only in basic phrases that every worker handling the listed chemicals should wear personal protective equipment (PPE) and does not consider the different hazard characteristics of particular chemicals or work types. The purpose of this study was to produce an exposure risk matrix and assign PPE to the categories of this matrix, which would be useful for revising the act to suggest PPE to suit work types or situations. Methods: An exposure risk matrix was made using hazard ranks of chemicals and workplace exposure risks in the previous study. For the 20 categories of exposure risk matrix PPE, levels A, B, C, D as classified by OSHA/EPA were assigned. After 69 hazardous chemicals were divided into 11 groups according to their physiochemical characteristics, respirators, chemical protective clothing (CPC), gloves and footwear were suggested on the basis of the assigned PPE levels. Results: PPE table sheets for the 11 groups were made on the basis of work types or situations. Full facepiece or half-mask for level C was recommended in accordance with the exposure risk matrix. Level A was, in particular, recommended for loading or unloading work. Level A PPE should be worn in an emergency involving hydrogen fluoride because of the number of recent related accidents in Korea. Conclusion: PPE assignment according to the exposure risk matrix made by chemical hazards and work type or situation was suggested for the first time. Each type of PPE was recommended for the grouped chemicals. The research will be usefully used for the revision of the Chemical Control Act in Korea.