• Korean Journal of Food Science and Technology
• /
• v.49 no.4
• /
• pp.408-414
• /
• 2017

Effects of pulsed electric field (PEF) processing on growth inhibition of indigenous aerobic microorganisms and the quality of mandarin and carrot juices were investigated. Mandarin juice was PEF-treated at 15-23 kV/cm for $23-241{\mu}s$, whereas carrot juice was treated at 13-14 kV/cm for 127-198 s. At $25^{\circ}C$ (inlet temperature), PEF treatments at 23 kV/cm for $104{\mu}s$ and 14 kV/cm for $198{\mu}s$ reduced the numbers of total mesophilic aerobes by $6.3{\pm}0.8$ and $5.5{\pm}0.9{\log}\;CFU/mL$ in mandarin juice and carrot juice, respectively. Elevation of inlet temperature to $40^{\circ}C$ increased the reduction rates in both juices. In general, the treatments resulting in the highest microbial inhibition at 25 and $40^{\circ}C$ did not alter the physicochemical and nutritional properties of both juices (p>0.05). PEF is a feasible technology to pasteurize mandarin and carrot juices commercially, with minimal quality deterioration.

• Food Science and Preservation
• /
• v.15 no.5
• /
• pp.731-735
• /
• 2008

The coliform group, Salmonella typhimurium and Staphylococcus were analyzed for eliminating of microorganism spore which could be embeded in honey and eradication of studied for heat resistance of thermoacidophilic bacteria was studied for marketing of honey after producing honey drink. The method for analyzing of heat resistance thermoacidophilic bacteria was membrane-seperated cell culture with $0.45\;{\mu}m$ micro-filter and vacuum aspirator. The results of bacteria, coliform group, Salmonella typhimurium and Staphylococcus was negative, but normal method such as sterilization with electrolyzed water, normal micro-filter, high-temperature heating and microwave did not have effect on heat resistance thermoacidophilic bacteria. Also, absolute type micro-filter of $0.45\;{\mu}m$ and $0.8\;{\mu}m$ microfilteration showed higher effect on heat resistance thermoacidophilic bacteria than micro-filter of normal type, showing negative results at all treatments.

• Proceedings of the KAIS Fall Conference
• /
• 2001.05a
• /
• pp.139-143
• /
• 2001

본 논문은 마이크로파를 이용하여 식품의 살균특성을 실험 한 것이다. 마이크로파의 살균특성을 실험하기 위해 공진 챔버와 개방형 흔 안테나를 설계 제작하고, 특성을 실험한 결과 매우 양호한 효과를 얻었다. 특히 식품 중에 수분의 함유량이 많은 식품으로서 변질될 우려가 심한 식품들은 마이크로파로 단시간 살균시킴으로서 유효기간을 장시간 연장할 수 있으므로, 변질로 인한 자원 낭비를 미연에 방지할 수 있고, 또한 인체에 해로운 방부제의 첨가를 제한할 수 있어 식품문화에 획기적인 전기를 가져올 수 있으리라고 본다.

• The Korean Journal of Pesticide Science
• /
• v.9 no.2
• /
• pp.132-139
• /
• 2005

New ${\beta}$-methoxyacrylate derivatives 1-4 having thio-enol side chain were prepared and subjected to in vivo screening for fungicidal activity against phytopathogenic fungi and many of them showed good fungicidal activities against especially rice blast and wheat leaf rust at 100 ppm.

• Korean Journal of Microbiology
• /
• v.37 no.2
• /
• pp.130-136
• /
• 2001

The killing effects of two types(one-phase reactor and two-phase reactor) of UV-TiO$_2$photocatalytic system on the microorganisms have been studied. The UV-lamp which emits maximum 39 watts at 254 nm was prepared in these system. Three types of $TiO_2$ coating method were adopted. One type is thin film coated form on the quartz tube in the reactor and another one is surface rough coated form on the glass bead. The other one is $TiO_2$-mixed alginate bead form. UV irradiation was carried out for 1 min. In case of one phase reactor, the bactericidal efficiencies of E. coli by $TiO_2$-coated quartz tube and $TiO_2$-coated glass bead were 63.2% and 89.9%, respectively. In the air-bubbling system, the bactericidal efficiency was 95%, however, the efficiency decreased to 90.6% in the non-bubbling system. In the $TiO_2$-mixed alginate bead system, bactericidal efficiency was 86%. When $H_2O$$_2$ was treated (10, 15, 20, and 25 mg/ι) to the $TiO_2$-coated glass bead reactor, bactericidal efficiency significantly increased according to the concentration of $H_2$$O_2$. Two phase reactor showed more elevated efficiency. E. coli was more sensitive to the reaction than S. cerevisiae.

• Korean Journal of Food Science and Technology
• /
• v.37 no.6
• /
• pp.1042-1047
• /
• 2005

Effects of sanitizers and disinfectants on microorganisms in food-processing plants were investigated. Chlorine and hydrogen peroxide were most effective, showing approximately 2-3 log reductions, among products tested, whereas alcohol showed less than 1 log reduction. Before using sanitizer and disinfectant in food processing plants, aerobic plate, coliforms, and E. coli counts were about $10^1-10^5,\;10^1-10^2$, and below $10\;CFU/cm^2$, respectively. After use of sanitizer, APC decreased to $10^1-10^2$. The result to confirm sanitizing effectiveness for 2 months using showed that Alcohol compound, QAC, hydrogen peroxide compound were effective against Staphylococcus aureus ATCC 6538 and E. coli ATCC 10536 at recommended usage concentrations, whereas effectiveness of chlorine compound decreased from 8 to 4 log 2 weeks after opening of product. Although sanitizers and disinfectants approved by law showed 5 log reduction in vitro for S. aureus ATCC 6538 and E, coli ATCC 10536, sanitizing effectiveness in food processing plants was very low, and effectiveness decreased once used product was stored.

• Journal of Korean Ophthalmic Optics Society
• /
• v.19 no.1
• /
• pp.59-67
• /
• 2014

Purpose: The present study was aimed to compare the results of disinfection efficacy tested by membrane filtration method with dilution-neutralization method to develop the standard methods for evaluating disinfection efficacy of contact lens care products and to provide the result of disinfection efficacy of commercially available contact lens care products in domestic market. Methods: The results of disinfection efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans evaluated by membrane filtration method as a FDA standard and dilution-neutralization method as newly being a KFDA standard were compared and the disinfection efficacy of 16 multi-purpose solutions was further evaluated. Results: The disinfectants and contact lens care products having strong disinfection efficacy showed same results in both membrane filtration method and dilution-neutralization method. In case of contact lens care products having weak disinfection efficacy, the number of micro-organisms was not able to count since the colony was aggregated when evaluated by membrane filtration method. However, the number of micro-organisms was able to exactly count when evaluated by dilution-neutralization method. In addition, some commercially available contact lens care products did not meet disinfection standard and especially, their disinfection effect was often weak against Serratia marcescen and Candida albicans. Conclusions: It is concluded that dilution-neutralization method will be useful to evaluate disinfection efficacy since it is possible to count micro-organisms more precisely even with small amount of sample and check the results faster compared with membrane filtration method.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.6
• /
• pp.912-917
• /
• 2011

The sterilization efficacies of various washing solutions on the surfaces of vegetables such as sesame leaves, lettuce, and mini-cabbage were investigated. The washing solutions were tap water (TW), microbubble water (MB), electrolyzed water (EW), and microbubble electrolyzed water (MB＋EW). After Escherichia coli and Bacillus cereus were artificially inoculated onto the surfaces of vegetables, each vegetable was washed for 1, 3, and 5 min with TW, MB, EW 100 (100 mg/L of available chlorine), EW 200 (200 mg/L of available chlorine), MB+EW 100, and MB＋EW 200. The washing efficacy of MB was slightly higher than that of TW, and EW was more effective than MB (p<0.05). In all instances, the sterilization efficacies of MB+EW 100 and MB+EW 200 were higher than those of EW 100 and EW 200 (p<0.05). Thus, MB+EW offers an effective means of reducing the studied microorganisms in a short time period. The MB＋EW washing method provides microbial reduction on the surfaces of various vegetables and enhances the microbiological safety of the vegetables.

• The Korean Journal of Pesticide Science
• /
• v.11 no.1
• /
• pp.18-26
• /
• 2007

Fungicidal screening was performed to control soybean black root rot caused by Calonectria ilicicola through in vitro and greenhouse assays. In in vitro assay, 25 fungicides were assessed by an agar dilution method and a 96-well microtiter plate method. While protective fungicides including dithianon, dichlofluanid, mancozeb, and captan showed a very low activity against the mycelial growth C. ilicicola SC03-15 in the agar dilution method, they displayed potent inhibitory activity against spore germination in a 96-well microtiter plate method with $EC_{50}$ values of 4.65, 0.61, 4.64, and $0.29{\mu}g\;mL^{-1}$, respectively. Ergosterol biosynthesis-inhibiting (EBI) fungicides showed different antifungal activity against mycelial growth and spore germination according to molecules. Difenconazole displayed higher antifungal activity against spore germination rather than mycelial growth, and prochloraz inhibited potently both mycelial growth and spore germination with EC50 values less than $1.8{\mu}g\;ml^{-1}$. In contrast, the other EBI fungicides inhibited more highly mycelial growth than spore germination. Carbendazim+diethofencarb and dazomet also inhibited both mycelial growth and spore germination of C. ilicicola SC03-15 at very low concentrations. In greenhouse assay, carbendazim+diethofencarb effectively controlled a soybean black root rot by drenching 2 days before or after inoculation. In addition, tebuconazole showed potent curative activity against soybean black root rot.

• Research in Plant Disease
• /
• v.22 no.3
• /
• pp.208-212
• /
• 2016

During the nursery seedlings stage at Muan in 2013, moisture and temperature conditions were favorable for the occurrence of onion downy mildew. Several fungicides were evaluated for controlling onion downy mildew at the stage of seedling. The disease incidence of the untreated control was 51.1%, which was sufficient to evaluate the fungicide efficacy for the control of onion downy mildew. Incidence at the mancozeb treatment (MAN treatment) was 4.4% and it was the highest control value of 91.4%. Incidence at the various fungicides treatment (MIX treatment) consisted of amectotradin plus dimethomorph, floupicolide plus propamocarb HCl, or dimethomorph plus pyraclostrobin was 10.0%, and the control value of the MIX treatment was 80.4%. Among the tested fungicides, amectotradin plus dimethomorph (AME plus DIM treatment) was selected and treated. Incidence of AME plus DIM treatment was 12.2%. There was statistically significant difference among the three different treatments and the untreated control. These results suggest that the application of fungicides on onion nursery seedlings was effective to control the onion downy mildew.