• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.6
• /
• pp.1295-1299
• /
• 2011

This study was conducted at the organic farming fields which garlics were planted. The treatments were as follows; water of $3,850L\;ha^{-1}$ (Control), plots applied 1 time, 2 times and 3 times with sea water of $3,850L\;ha^{-1}$. In 3 times sea water treatment plot, the level of EC, Exch. Na and $Cl^-$ were 1.1, 2.1, and 3.3 times higher than control plot, respectively. Due to seawater application, the contents of inorganic elements such as T-N, Ca, Mg, Na, Fe, Mn, and Zn in garlic were generally lower than Control, but not significant.

• Journal of Food Hygiene and Safety
• /
• v.37 no.2
• /
• pp.55-62
• /
• 2022

The bacterial soft-rot disease is one of the most critical diseases in vegetables such as Chinese cabbage. The researchers isolated two bacteria (Pseudomonas kribbensis and Pantoea vagans) from diseased tissue samples of Chinese cabbages and confirmed them as being the strains that cause soft-rot disease. Lactic-acid bacteria (LAB), were screened and used to control soft-rot disease bacteria. The researchers tested the treatments with hypochlorous acid water (HAW) and LAB supernatant to control soft-rot disease bacteria. The tests confirmed that treatments with the HAW (over 120 ppm) or LAB (Lactobacillus plantarum PL203) culture supernatants (0.5 mL) completely controlled both P. kribbensis and P. vagans.

• Applied Chemistry for Engineering
• /
• v.19 no.1
• /
• pp.122-128
• /
• 2008

We evaluated the relationship between the multiplication of heterotrophic microorganisms and physicochemical factors in the final discharged sewage water from J municipal waste water treatment plants. Dissolved organic carbon (DOC) was the most crucial factor influencing multiplication of heterotrophic plate counts (HPC) among the water quality variables selected. Degrading bacteria, such as proteolytic bacteria, lipholytic bacteria, starch degrading bacteria, cellulolytic bacteria, and pectinolytic bacteria, were monitored to understand the condition of nutrients in finished sewage effluent. The percentages of lipid and protein combined occupied 81% in finished sewage water. The multiplication of HPC showed the highest value in August. The formation of trihalomethane (THM) was low in the finished discharge water during chlorine disinfection, which was $71{\mu}/L$ (which was less than $100{\mu}/L$- the standard of drinking water quality) with 10 mg/L of chlorine during 15 min.

• Analytical Science and Technology
• /
• v.23 no.6
• /
• pp.551-559
• /
• 2010

This study was conducted to establish an analytical method for the determination of seven nitrosamines in chlorinated tap water by precolumn derivatization followed by high performance liquid chromatography coupled with fluorescence detection. The derivatization procedure was optimized for denitrosation and dansylation, and then two extraction methods, liquid-liquid extraction (LLE) with dichloromethane and solid phase extraction (SPE), were compared. The SPE method employing the optimized derivation procedure showed higher extraction recovery (54.4-88.7%) and reproducibility (1.9-19.4%) than the LLE method (51.4-87.7% and 4.2-33.3%, respectively). The method detection limits were between 0.5 and 4.4 ng/L. When chlorinated water samples were collected from two treatment plants and ten household taps, and analyzed for nitrosamines, Nnitrosodimethylamine (NDMA) was the major compound found between 26.1 and 112 ng/L.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.5
• /
• pp.446-456
• /
• 2001

This study was carried out for the dietry safely based on the level of pesticide residues In 13 kinds of agricultural products consumed in Kyonggi-Do. Korea. From June to October 2000, sixteen organochlorine pesticides in 397 samples were analyzed by using GC/ECD and GC/MSD. According to the results, endosulfan were detected in 27(7.8%) samples and chlorothalonil were detected in 4(1.0%) samples. Detection ranges of endosulfan were 3.7437∼ 0.0488ppm for lettuce, 2.1902 ∼0.1423ppm for spinach, 2.4909 ∼0.0786ppm for mallow and 3.2333∼0.3997ppm for mustard leaf, respectively Chlorothalonil were 5.8097 for lettuce and 0.8962ppm for spinach. Consequently, six agricutural products were detected more than the maximum residue limits in Korea Endosulfan were detected In 5(1.8%) samples and cholrothalonil were detected in 1(0.3%) sample. Detection rates of endosulfan sulfate(45.9%) of agricultural products were more than $\alpha$-endosulfan(28.5% ) and $\beta$-endosulfan (23.9% ) .

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.8
• /
• pp.1233-1238
• /
• 2016

Combined treatment of chlorine dioxide ($ClO_2$) gas, mild heat, and fumaric acid was performed to reduce microbial growth and maintain quality of Citrus unshiu during storage at $4^{\circ}C$. Citrus unshiu fruits were treated with $ClO_2$ gas (15 or 30 ppmv), mild heat (40, 50, or $60^{\circ}C$), and fumaric acid (0.1, 0.3, or 0.5%). Combined treatment of 15 or 30 ppmv $ClO_2$ gas, $50^{\circ}C$ mild heat, and 0.5% fumaric acid reduced populations of inoculated Listeria monocytogenes by 3.5~3.7 log CFU/g. In addition, combined treatment decreased populations of yeast and molds in Citrus unshiu by 2.54 log CFU/g after 30-day storage at $4^{\circ}C$. Combined treatment also reduced the decay rate by 48% after 30 days of storage compared with the control. Total solid content, titratable acidity, and color values were not significantly affected by the combined treatment. Therefore, combined treatment of $ClO_2$ gas, mild heat, and fumaric acid can be a useful hurdle technology to improve microbial safety and quality of Citrus unshiu during storage.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.581-584
• /
• 2008

Generally, durability of concrete structures under marine environment is grossly declined by detrimental ions such as chlorides, which penetrate concrete and was diffused to corrode reinforcing rod. Therefore, chloride diffusion properties in concrete are important for durability evaluation and design of concrete structure. For estimation of chloride diffusion coefficient in concrete, both evaluation methods are used for steady state and non-steady state derived from Fick's 1st and 2nd law, respectively. However, as it is very difficult to evaluate diffusion coefficient for non-steady state like service environment where concrete is actually exposed, indirect evaluation method by laboratory accelerated test is generally used. In this study, comparison of chloride diffusion behavior was investigated for fixed mix proportion and age of concrete using four accelerated test methods based on domestic and foreign standards. From test results, only relative comparison between concrete mixtures was possible using ASTM C 1202 test, and diffusion coefficient for steady state was estimated as low as 1/10 of that for non-steady state. In addition, diffusion coefficient estimated by immersion test was similar to result by NT build 492 test.

• Korean Journal of Food Science and Technology
• /
• v.39 no.2
• /
• pp.222-227
• /
• 2007

The effects of chlorine dioxide ($ClO_2$) treatment on the quality changes of pork and beef were examined. Pork belly and beef tenderloin samples were treated with 30, 50, and 100 ppm of $ClO_2$ solution, respectively, and stored at $4{\pm}1^{\circ}C$. The $ClO_2$ treatment of pork and beef during storage decreased total aerobic bacteria, yeast, and mold counts with increasing concentration of $ClO_2$. The total aerobic bacterial counts for the pork belly treated at 100 ppm of $ClO_2$ increased from 1.48 log CFU/g immediately following treatment to 4.73 log CFU/g after 10 days, while the control increased from 2.19 log CFU/g to 6.22 log CFU/g. For the beef tenderloin, the total aerobic bacterial counts increased from 3.98 log CFU/g to 5.97 log CFU/g after 10 days, and a $ClO_2$ treatment at 100 ppm resulted in an increase from 3.13 log CFU/g to 4.73 log CFU/g. The pH and volatile basic nitrogen (VBN) values of the $ClO_2-treated$ pork and beef, as well as the control groups, increased during storage, and there were no significant changes among the treatments. The thiobarbituric acid reactive substance (TBARS) values of the $ClO_2-treated$ samples were slightly higher than those of the control. Sensory evaluation results showed that the pork and beef samples were not acceptable at day 8 and 6 of storage, respectively. These results indicate that $ClO_2$ treatment could be useful in improving microbial safety and quality of both pork and beef.

• Journal of Bio-Environment Control
• /
• v.21 no.4
• /
• pp.411-418
• /
• 2012

This study was conducted to investigate the effect of calcinated calcium (CC) alone or combination with heat treatment on storage quality and microbial growth in fresh-cut broccoli. Fresh broccoli samples were cut into small pieces and washed in normal tap water (TW), $50{\mu}L{\cdot}L^{-1}$ chlorinated water (pH 6.5), $1.5g{\cdot}L^{-1}$ CC, heat treatment in TW at $45^{\circ}C$, and CC dissolved in TW at $45^{\circ}C$ for 2 minutes separately. Samples were then packaged in $50{\mu}m$ polyethylene bags and stored at $5^{\circ}C$. Results revealed that like $50{\mu}L{\cdot}L^{-1}$ chlorine, washing in CC at normal water temperature was effective in reducing microbial population in fresh-cut broccoli samples. Washing with CC combined with heat treatment increased an electrical conductivity of fresh-cut broccoli. Combined heat treatments with TW and CC reduced aerobic plate count on fresh-cut broccoli, only in initial period of storage. But, later on heat treatment induced injury of fresh-cut broccoli resulting more microbial population compared to non heat treatment. However, samples treated with CC alone had good quality with low off-odor at the end of storage. Results suggest that CC, an environment-friendly sanitizer could be an alternative to chlorinated water for washing of fresh-cut broccoli without affecting sensorial quality.

• Resources Recycling
• /
• v.17 no.2
• /
• pp.70-75
• /
• 2008

A study on the cementation for the recovery of tin with aluminium in the hydrochloric acid solution was carried out. Parameters, such as aluminium metal equivalent, pH, reaction time, reaction temperature and the concentration of chloride ions were investigated. The experimental results showed that the cementation rate of Sn(II) ions increased with increase of the addition amount of aluminium powders, temperature, pH and the concentration of chloride ions in hydrochloric acid solution. From the results, the optinum conditions for recovery of metallic tin by cementation with aluminium metal powders were proposed.