• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.509-516
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• 1998

Thermoluminescence measurements were applied to the detection of seasoned-powered foods such as shellfish extract powder, seasoned marine products, Ramen soup powder and sardine extract powder whether they are irradiated or not. Correlation coefficients $(R^2)$ between irradiation doses and corresponding TL responses were more than 0.5966 in all samples and 0.9500 in Ramen soup powder. TL threshold value was pre-established for the detection of unknown Ramen soup powders by verifying TL responses with a re-irradiation step. Threshold values were maximum 1.37 for the nonirradiated samples and minimum 6.06 for the 2.5 kGy-irradiated samples. The samples showing values between 1.37 and 6.06 were subjected to a re-irradiation step for their detection, which results were reconfirmed by enumerating the total bacterial load of the detected samples. Pre-established threshold values were successfully applicable to the detection of 167 coded unknown samples, both nonirradiated and irradiated with gamma or electron-beam energy. In the assessment of irradiated doses, three calibration curves were pre-established by plotting TL intensity versus applied doses, of which a quadratic equation was obtained for the potential estimation of irradiated doses with some variations from the real doses.

• Food Science and Preservation
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• v.14 no.6
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• pp.598-604
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• 2007

Process development and standardization are necessary in maintaining high hygienicquality of side dishes. Seasoned perilla leaves are a typical side dish needing process development. In this study the optimum condition for preparing seasoned perilla leaves was investigated experimentally. The best sensory quality was established by response surface methodology. The rinsing and washing method of preparing fresh perilla leaves was optimized to decontaminate the raw material and preserve the product in chilled storage. Washing and rising with 3% salt water reduced the aerobic bacterial count of perilla leaves to 0.55 (log CFU/g), while rinsing reduced the load from 8.08 to 4.27 (log CFU/g). The effect of rinsing method was maintained during subsequent storage of the prepared seasoned leaves at $10^{\circ}C$. There was no significant quality change in the product during chilled storage at $10^{\circ}C$. Soaking in 3% salt water for 1 min, followed by rinsing with tap water, contributed positively to the microbial quality, and is proposed as the optimal preparation method.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.239-245
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• 2004

Storage quality of minimally processed onion as influenced by hot-water dipping was investigated to examine feasibility of mild heat treatment as efficient post-processing method. fresh onions were peeled, trimmed, and dipped in hot water at various temperatures ($50-80^{\circ}C$) for 1 min. Heat-treated onions were cooled, de-watered, packaged in low density polyethylene (LDPE) film pouches ($63\;{\mu}m\;thickness$), and stored at $10^{\circ}C$. Samples treated at higher temperatures ($70-80^{\circ}C$) showed significant increases in flesh weight loss and discoloration during storage as compared to others. Hot-water dipping remarkably reduced initial microbial load of prepeeled onions, with over 1 log cycle decrease in aerobic bacterial count. After 7 days storage, no significant differences in viable aerobe count were observed among treated and untreated samples, with both showing $10^{6}-10^{7}\;CFU/g$. For sensory attributes including discoloration, wilting, decay, and visual quality, onions treated with hot-water dipping at $60^{\circ}C$ scored highest. Results suggested hot-water dipping at specific condition as practical post-processing treatment could effectively prolong shelf life of minimally processed onion.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.11-18
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• 2008

Seasonal succession and community composition of planktonic ciliates were studied in Kyungan Stream from December 2000 to December 2001. Oligotrichs accounted for 53% of total ciliates. Total abundance of ciliates peaked in spring (30 March, 6 April) and in summer (8 June, 20 July) reaching values up to $1.9\times10^4$ cells $L^{-1}$. Seasonal succession of dominant species occurred obviously. Large-sized $(>50{\mu}m)$ species (Stylonychia sp1, Phascolodon vorticella and Codonella cratera) dominanted from winter to spring. Small sized $(<30{\mu}m)$ species (Vorticella spp., Rimostrombidium hyalinum and Halteria grandinella) dominanted in summer and autumn. Total abundance of large-sized species coincided with the Chl-${\alpha}$ concencetation during the study (r=0.33, p<0.05, n=39). Among the small-sized species Halteria grandinella was a significant relationship with bacterial abundance (r=0.35, p<0.05, n=39).

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.444-450
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• 2022

The effect of coated polyester (PET) textiles with metal oxide, chitosan, and copper ion on the antibacterial and antiviral activities was evaluated to investigate the applicability of multi-coated PET textiles as antiviral materials. Compared to coated PETs with a single agent, multi-coated PETs reduced the loading amount of coating materials as well as the contact time with bacteria for a bacterial cell number of < 10 CFU/mL, which was not detectable with the naked eyes. Metal oxides generate reactive oxygen species (ROS) such as free radicals by a catalytic reaction, and copper ions can promote contact killing by the generation of ROS. Chitosan not only enhanced antibacterial activities due to amine groups, but enabled it to be a template to load copper ions. We observed that multi-coated PET textiles have both antibacterial activities for E. coli and S. aureus and antiviral efficiency of more than 99.9% for influenza A (H1N1) and SARS-CoV-2. The multi-coated PET textiles could also be prepared via a roll-to-roll coating process, which showed high antiviral efficacy, demonstrating its potential use in air filtration and antiviral products such as masks and personal protective equipment.

• Journal of Food Hygiene and Safety
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• v.8 no.3
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• pp.135-140
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• 1993

Dried fishes such as dried pollack, dried sliced squid, dried white bait, dried anchoy) and dried cod used to cook Korean traditional foods were airpacked in polyethylene tube and irradiated with 7 kGy of gamma-ray source. The effect of gamma irradiation on microbial growth in dried fishes was investigated during storage at ambient temperature for 12 months. The total aerobic bacteria in the control group were contaminated by $3.9{\times}10^{3}\;cells/g$ in dried pollack, $5.6{\times}10^{5}\;cells/g$ in dried sliced squid, $1.2{\times}10^{5}\;cells/g$ in dried white bait, $1.2{\times}10^{4}\;cells/g$ in dried anchovy and $1.2{\times}10^{4}\;cells/g$ in dried cod and 7 kGy irradiation could eliminate the bacteria and also reduce aerobic bacterial load to 1~3 log cycle and no apparent growth of microorganisms occurred during storage. Molds in the control group were contaminated by $4.0{\times}10^{2}\;cells/g$ in dried pollack, $$1.3{\times}10^{2}\;cells/g$ in dried sliced squid, $2.5{\times}10^{2}\;cells/g$ in dried white bait, 90 cells/g in dried anchovy and $2.0{\times}10^{2}\;cells/g$ in dried cod, respectively. 7 kGy irradiation could sterilize the molds and the growth of molds of nonirradiated samples were slightly decreased during storage. Yeasts in the control group were contaminated by $1.4{\times}10^{3}\;cells/g$ in dried poUack, 75 cells/g in dried sliced squid, $1.1{\times}10^{3}\;cells/g$ in dried white bait, 50 cells/g in dried anchovy, $1.6{\times}10^{2}\;cells/g$ in dried cod, respectively and irradiation could sterilize the yeasts and growth of yeasts was slightly decreased in dried pollack and dried white bait but increased in order of dried anchovy, dried cod and dried sliced squid. Coliforms in all sample were sterilized by irradiation and its growth was decreased during storage except dried anchovy.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.35-43
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• 2024

Numerous methods have been applied to assess the antibacterial effectiveness of hand hygiene products. However, the different results obtained through various evaluation methods have complicated our understanding of the real efficacy of the products. Few studies have compared test methods for assessing the efficacy of hand hygiene products. In particular, reports on ex vivo pig skin testing are limited. This study aimed to compare and characterize the methodologies applied for evaluating hand hygiene products, involving in vitro, ex vivo, and in vivo approaches, applicable to both leave-on sanitizers and wash-off products. Our further aim was to enhance the reliability of ex vivo test protocols by identifying influential factors. We performed an in vitro method (EN1276) and an in vivo test (EN1499 and ASTM2755) with at least 20 participants, against Serratia marcescens or Escherichia coli and Staphylococcus aureus. For the ex vivo experiment, we used pig skin squares prepared in the same way as those used in the in vivo test method and determined the optimal treated sample volumes for sanitizers and the amount of water required to wash off the product. The hand sanitizers showed at least a 5-log reduction in bacterial load in the in vitro test, while they showed little antibacterial activity in the in vivo and ex vivo tests, particularly those with a low alcohol content. For the hand wash products, the in vitro test was limited because of bubble formation or the high viscosity of the products and it showed low antibacterial activity of less than a 1-log reduction against E. coli. In contrast, significantly higher log reductions were observed in ex vivo and in vivo tests, consistently demonstrating these results across the two methods. Our findings revealed that the ex vivo and in vivo tests reflect the two different antibacterial mechanisms of leave-on and wash-off products. Our proposed optimized ex vivo test was more rapid and more precise than the in vitro test to evaluate antibacterial results.