• 한국미생물·생명공학회지
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• 제50권1호
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• pp.95-101
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• 2022

Due to the pandemic caused by COVID-19, the demand for face masks is soaring and has often caused a shortage. The aim of this study was to evaluate the effect of ultraviolet (UV) and drying treatments on microbial contaminants in facial masks. To conduct this study, standard procedures were designed to develop samples contaminated by the control bacteria Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The contamination level of the standard samples was approximately 6.30 × 10⁶ CFU/ml, and the UV light treatment was performed 1, 3, 5, and 7 times. To evaluate the effect of the UV and drying treatments, the masks were first treated with UV 1, 2, and 3 times, followed by the drying process. As a result, the mask contaminated with E. coli and P. aeruginosa showed a bacterial rate of approximately 99.9% after 1 UV irradiation, and in the case of the S. aureus-contaminated mask, it exhibited a bactericidal rate of approximately 99.9% after 7 UV irradiations. However, when the drying process was included after UV irradiation, all the samples contaminated with E. coli, S. aureus, and P. aeruginosa showed a bactericidal rate of 99.9% or more. The results of this study suggest that UV and drying treatments can effectively reduce the bacterial contaminants in facial masks. In addition, these results provide fundamental data and appropriate sterilization methods for reusing masks.

• 한국응용과학기술학회지
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• 제32권3호
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• pp.412-417
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• 2015

2차 오염이 없는 물리적 선박 평형수 처리 장치의 조합별 비교를 통하여 비교적 우수한 조합을 밝혀내는 것이 본 연구의 목적이다. 2008년 IMO에서는 선박 평형수 문제를 제제하기 위해 배출 선박 평형수 내 미생물의 농도를 일정 농도로 규제하게 되었다. IMO 규제 농도를 맞추기 위한 멸균 방법으로는 약품을 이용한 화학적 처리, 전기분해를 통한 차아염소산 처리, UV나 오존 및 플라즈마를 이용하는 방법, membrane을 이용하는 방법 등이 있다. 하지만 어느 방법이나 부분적으로 2차오염이나 선체부식 및 살균효율 등의 단점을 가지고 있는 실정이다. 아울러 이런 단점들을 피해가면서 조류와 미생물을 효율적으로 멸균 시킬 수 있는 방법은 현재까지 미비한 실정이다. 본 연구에서 적용된 처리장치는 전단응력을 이용하여 2차 오염을 발생시키지 않으면서 조류와 미생물을 살균시킬 수 있는 물리적 살균처리장치이다. 본 연구에서는 이 장치의 다양한 type별 조합으로 실험하여 살균 가능한 최저 회전속도에 따른 최고 유량 등을 규명하여 상업적 처리 장치의 설계를 위한 기초자료로 삼고자하였다.

• Journal of Dairy Science and Biotechnology
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• 제35권2호
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• pp.121-133
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• 2017

A small amount of milk is sold as 'untreated' or raw in the US; the two most commonly used heat-treatments for milk sold in retail markets are pasteurization (LTLT, low-temperature long time; HTST, high-temperature short time) and sterilization (UHT, ultra-high temperature). These treatments extend the shelf life of milk. The main purpose of heat treatment is to reduce pathogenic and perishable microbial populations, inactivate enzymes, and minimize chemical reactions and physical changes. Milk UHT processing combined with aseptic packaging has been introduced to produce shelf-stable products with less chemical damage than sterile milk in containers. Two basic principles of UHT treatment distinguish this method from in-container sterilization. First, for the same germicidal effect, HTST treatments (as in UHT) use less chemicals than cold-long treatment (as in in-container sterilization). This is because Q10, the relative change in the reaction rate with a temperature change of $10^{\circ}C$, is lower than the chemical change during bacterial killing. Based on Q10 values of 3 and 10, the chemical change at $145^{\circ}C$ for the same germicidal effect is only 2.7% at $115^{\circ}C$. The second principle is that the need to inactivate thermophilic bacterial spores (Bacillus cereus and Clostridium perfringens, etc.) determines the minimum time and temperature, while determining the maximum time and temperature at which undesirable chemical changes such as undesirable flavors, color changes, and vitamin breakdown should be minimized.

• 한국식품과학회지
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• 제45권2호
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• pp.248-251
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• 2013

김에 존재하는 M. roseus는 비병원성 세균이나 사람이 면역력이 떨어지게되면 질병을 일으킬 수 있는 균주로서 열처리를 통해서도 쉽게 사멸되지 않고 특히 10 kGy의 감마선 조사에서도 1 log, 40 kGy의 조사선량에서 1 log CFU/mL 이상의 생존율을 나타내는 방사선 저항 세균이다. 이러한 방사선 저항 세균인 M. roseus를 광펄스 살균을 통해 살균 가능성을 알아보았다. M. roseus는 빛의 세기가 증가함에 따라 사멸율이 증가하는 경향을 나타냈으며, 1,000 V의 빛의 세기에서 3분 처리 후에 6.4 log의 감소효과를 보였고 tailing 현상을 보이지 않았다. 빛의 세기와 처리시간을 같이 한 조건에서는 단위 시간동안 펄스 수가 높을수록 살균율이 높아졌으며, 10 pps에서는 2분의 처리로 모든 균이 사멸하였다. 또한 광원과 시료사이의 거리는 가까울수록 사멸율이 증가하는 경향을 보였다. 이러한 연구 결과로 볼 때 광펄스 살균이 향후 김의 위생적 처리의 방법의 하나로 가능성이 있을 것으로 예측된다.

• Journal of Biosystems Engineering
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• 제26권4호
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• pp.391-398
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• 2001

A robot system for clone replication and gridding, which is a preliminary state of the genome research, was developed and evaluated its performance. This gridding robot system consisted of 1) a gridding heat that replicated the clone, 2) a manipulator, as a part of body of robot, which transferred the gridding head along x-, y-, z-axis, 3) a well plate arranging board, 4) a sterilization unit, and 5) a control unit. Performance of the system was evaluated with 1) repeatability of the robot system, 2) clone replication efficiency, 3) time requirement of the replication, and 4) sterilization efficiency. The repeatability error of the robot system showed 0.219 mm and 0.094 mm in the direction of x- and y-axis, respectively. The success rate of the clone replication with the gridding head was 100% on the membrane filter. The time required for the replication was four minutes and fifty-five seconds from the four 96 well plates to a 384 well plate meanwhile the required time with well experienced hand labor was three minutes thirty-five seconds. The gridding operation of clone could not be done by hand labor and the required time with robot system for the gridding on the membrance filter with the control program 5$\times$5: 1 copy and 384 gridding pins was twenty minutes and twenty-five seconds. The efficiency of the sterilization was considered to be satisfactory since no growth of fungi was found around the area of replication in the membrane filter.

• 한국식품과학회지
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• 제47권4호
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• pp.474-479
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• 2015

연속식 옴가열 장치를 이용한 고추장을 베이스로 한 모델 식품에 대한 가열 살균 연구를 진행하여, 옴가열을 이용한 소스 살균에 필요한 기초 데이터를 수집하였다. 옴가열 시 점도에 상관없이 $100^{\circ}C$까지 고르게 상승하였으나, 점도가 높을수록 전기전도도와 가열속도가 낮아져 살균력이 감소하는 것으로 나타나, 저점도 식품이 옴가열을 이용한 가열 및 살균에 있어 더 유용하다는 것을 알 수 있었다(13,14). 재래가열 후의 살균도는 65.4-75.4%, 옴가열 시는 89.5-95.0%로 살균력이 더 우수하였다. 향후 연속식 옴가열 장치의 살균효과를 더 높이기 위해서는 여러 개의 셀 연결 방식을 통해 한 개의 셀에서 온도를 조금씩 상승시켜 스케일 생성을 방지하는 연구와 셀 통과시 빠른 온도 상승에 의한 점도 변화로 살균 처리량이 변하기 때문에 최적 셀 조합 및 가열살균 조건에 대한 충분한 고찰이 필요할 것으로 생각된다.

• Journal of Ginseng Research
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• 제45권4호
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• pp.519-526
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• 2021

Background: This study aimed to investigate the effect of cold plasma treatment on the improvement of seed germination and surface sterilization of ginseng seeds. Methods: Dehisced ginseng (Panax ginseng) seeds were exposed to dielectric barrier discharge (DBD) plasma operated in argon (Ar) or an argon/oxygen mixture (Ar/O₂), and the resulting germination and surface sterilization were compared with those of an untreated control group. Bacterial and fungal detection assays were performed for plasma-treated ginseng seeds after serial dilution of surface-washed suspensions. The microbial colonies (fungi and bacteria) were classified according to their phenotypical morphologies and identified by molecular analysis. Furthermore, the effect of cold plasma treatment on the in vitro antifungal activity and suppression of Cylindrocarpon destructans in 4-year-old ginseng root discs was investigated. Results: Seeds treated with plasma in Ar or Ar/O₂ exhibited a higher germination rate (%) compared with the untreated controls. Furthermore, the plasma treatment exhibited bactericidal and fungicidal effects on the seed surface, and the latter effect was stronger than the former. In addition, plasma treatment exhibited in vitro antifungal activity against C. destructans and reduced the disease severity (%) of root rot in 4-year-old ginseng root discs. The results demonstrate the stimulatory effect of plasma treatment on seed germination, surface sterilization, and root rot disease suppression in ginseng. Conclusion: The results of this study indicate that the cold plasma treatment can suppress the microbial community on the seed surface root rot in ginseng.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2006년도 한국약용작물학회 공동춘계학술발표회
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• pp.380-381
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• 2006

• Journal of Biosystems Engineering
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• 제28권5호
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• pp.449-456
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• 2003

A robot system was developed to pick desired colony. This robot system consisted of an image acquisition process which acquires the image information of colony, an illumination device which irradiates the object once when it gets the image of it, a picking head, a replicating head, a bed for fixing well-plates, and a sterilization device of sterilizing pin stained with colony. Picking pins were washed in an ultrasonic wave washing for takes ten seconds. Picking pins were dipped for sterilizing in alcohol for ten seconds. The time for resterilizing picking pins in a heater was five seconds. This performance test resulted 100% success rate for both the colony picking and the colony replication process. Considering the procedure in which 8 pins were smeared by colony, picked on a well plate, and sterilized as one cycle, the system could carry out one cycle in 110 seconds. It took about 138 minutes to pick around 600 colonies.

• 산업기술연구
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• 제3권
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• pp.87-94
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• 1983

Heating characteristics of red pepper paste packed in report pouches of various thicknesses and their storage stability were investigated to determine the adequate processing conditions that good bacteriological safty and minimal quality changes could be obtained, when sterilized by using a steam-air system retort. A heat penetration into pouch-packed red pepper paste was carried out through by a conductive heat transfer, indicating a simple logarithmic heating curve, and the smaller thickness revealed the higher heat penetration rate, suggesting the possibility of high temperature-short time sterilization of red pepper paste. The processing conditions with Fo-value of 4.5 or higher were sufficient for keeping up bacterial safty, but based on C-value, better quality retention was obtained at pouch thickness of 15mm under the processing temperature of $120^{\circ}C$. Subsequent storage study revealed that the red pepper paste packed in 15mm and processed at $120^{\circ}C$ with Fo=4.5 could be held without any spoilage and overall acceptance change, when stored for 6 months at room temperature under the relative humidity of 70%. After 3 months storage in $38^{\circ}C$ under saturation humidity, overall acceptance of red pepper paste were judged not to be maintainable on the acceptable level, but it may be suggested that above the results could be kept up a desirable quality without any remarkable deterioration.