• Food Science and Biotechnology
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• 제18권5호
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• pp.1243-1252
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• 2009

User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

• 식물병연구
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• 제17권1호
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• pp.38-43
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• 2011

채소류가 소비되기까지 약 10~30%에 이르는 양이 부패에 의해 버려지고 있다. 채소류는 수확 후 수많은 세균이나 곰팡이와 같은 다양한 미생물들에 의해 부패가 이루어진다. 채소류의 부패와 세균과의 관계를 알아보고자 세균의 다양성에 관한 조사를 하였다. 신선한 상추와 깻잎, 치커리에서의 총 호기성 균 수는 각각 $2.6{\sim}2.7{\times}10^6$, $4.6{\times}10^5$, $1.2{\times}10^6\;CFU/g$ of fresh weight이었으며, Pseudomonas spp., Alysiella spp., Burkholderia spp.와 그 외의 18개의 다양한 속들이 확인되었다. 신선한 채소류를 $28^{\circ}C$에서 일주일 동안 배양하였을 때 세균 다양성에 변화가 생겼다. 총 호기성 균의 수는 상추와 깻잎, 치커리에 대하여 각각 $1.1{\sim}4.6{\times}10^8$, $4.9{\times}10^7$, $7.6{\times}10^8\;CFU/g$ of fresh weight로 나타났으며, 이는 약 $10^2$배 정도 증가한 수치이다. 하지만 세균 다양성은 단순해져서 보다 적은 수의 세균이 분리, 동정되었다. Pseudomonas spp.가 대부분을 차지하였으며(~48%), Arthrobacter sp., Bacillus sp.가 그 뒤를 이었다. 동정된 세균 각각의 부패능을 검정하고자 무균배양한 상추에 접종하였으며, 그 결과 Pseudomonas fluorescence와 Pantoea agglomerans가 상당한 부패를 야기하였다.

• Journal of Biosystems Engineering
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• 제30권1호
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• pp.17-24
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• 2005

An efficient microbial control system was introduced into a garlic peeling system using pressurized water in order to improve the quality and the shelf-life of peeled garlic. High microbial density of the spoiled peeled garlic and the water used for peeling and washing indicated that an efficient microbial control system is necessary far the peeling system. Though Pseudomonas spp. and Penicillium spp. were closely related to the spoilage of peeled garlic, the spoilage of peeled garlic was thought to be caused mainly by nonspecific increase in microbial density. The shelf-life of the garlic peeled by pressurized water was longer than that of the garlic peeled by pressurized air, and the degree of damage had great effect on the shelf-life of peeled garlic. Ozonated water was effective in decreasing the microbial contamination and in increasing the shelf-life of peeled garlic. Based on the findings of the study, following improvements were made to the garlic peeling system using pressurized water; 1) the water circulation system was modified in order to completely separate the water for washing from the water for garlic peeling, 2) filtration and cooling equipments were introduced into the circulation system of the water for peeling, and 3) an ozone generator which could continuously supply ozonated water (dissolved ozone concentration of 0.4 ppm) was attached to the circulation system of the water for washing.

• 식품과학과 산업
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• 제52권3호
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• pp.220-228
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• 2019

Rapid development of next-generation sequencing (NGS) technology is available to study microbes in genomic level. This NGS has been widely used in DNA/RNA sequencing for genome sequencing, metagenomics, and transcriptomics. The food microbiology area could be categorized into three groups. Food microbes including probiotics and food-borne pathogens are studied in genomic level using NGS for microbial genomics. While food fermentation or food spoilage are more complicated, their genomic study needs to be done with metagenomics using NGS for compositional analysis. Furthermore, because microbial response in food environments are also important to understand their roles in food fermentation or spoilage, pattern analysis of RNA expression in the specific food microbe is conducted using RNA-Seq. These microbial genomics, metagenomics, and transcriptomics for food fermentation and spoilage would extend our knowledge on effective utilization of fermenting bacteria for health promotion as well as efficient control of food-borne pathogens for food safety.

• 한국축산식품학회지
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• 제33권4호
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• pp.439-447
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• 2013

Time-temperature integrators (TTIs) are simple and cost-efficient tools which may be used to predict food quality. Enzymatic TTIs are devised to indicate food quality in the form of color alterations from green to red, based on the cumulative impacts of temperature and time period on the enzymatic reactions. In this study, the quality of ground beef patties was investigated for the parameters of pH levels, color, VBN, water holding capacity, and total microbial counts, depending on various storage temperatures (5, 15, and $25^{\circ}C$). TTIs were attached to the surface of the ground beef patties in order to evaluate the degree of correlating colorimetric changes with the determined quality parameters. Through the Arrhenius equation, activation energy and constant reaction rates of TTI, VBN, and total microbial counts were calculated as to observe the relationship between enzymatic reactions of the TTI and food spoilage reactions of the ground beef patties. VBN and total microbial counts were already increased to reach decomposition index (VBN: 20, total microbial count: 7-8 Log CFU/g) of meat at middle stage of storage period for each storage temperature. Although activation energy of TTI enzymatic reactions and food spoilage reactions of the ground beef patties were similar, the change of TTI color was not a coincidence for food spoilage at $5^{\circ}C$ and $15^{\circ}C$ of storage temperature. It was suggested that TTI should be designed individually for storage temperature, time, type of meat, or decomposition index of meat.

• 농업생명과학연구
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• 제50권1호
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• pp.1-22
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• 2016

본 연구에서는 농업 분야 유용미생물 자원의 국가적 확보 현황을 파악하기 위해 이들의 생물분류학적 정보를 수집하였으며 이들에 대해 생물 종 다양성 지수를 도입하여 평가하였다. 대표적인 생물다양성 평가방법인 Margalef's richness 및 Mehinick's index를 각각 적용한 경우 세균은 각각 8.537, 3.546, 진균은 각각 3.349, 2.167의 값을 나타내었다. 높은 수준의 다양성을 가지고 연구·개발되고 있는 이들 농업 분야 유용미생물 및 농산물의 수확 후 선도저하를 유발한다고 보고된 주요 미생물들의 분류학적 위치를 비교하였을 때 일부 미생물이 유사한 분류학적 위치를 보이는 것이 확인되었다. 따라서 친환경농업 분야 유용미생물의 연구개발 및 작물 내생 미생물에 관한 연구 등 농업 분야 미생물에 대한 전반적인 연구현황을 고찰하여 농산물의 수확 후 선도관리를 위한 보완책을 제시하고자 하였다.

• Preventive Nutrition and Food Science
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• 제8권1호
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• pp.89-92
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• 2003

The effect of gamma-irradiation on microbiological growth in kale juice during storage was studied. Fresh kale juice was prepared and irradiated at 0, 1, 3, 5, 7, 10, and 15 kGy. D values for total bacteria, yeast and mold, Salmonella, E. coli, and Pseudomonas were 3.6, 4.0, 3.2, 1.4, and 1.6 kGy, respectively. E. coli and Pseudomonas were eliminated completely at 5 and 7 kGy, respectively. Gamma-irradiation also reduced total viable bacteria during storage. Therefore, these results indicate gamma-irradiation can prevent microbial spoilage of fresh kale juice by inactivating pathogenic microorganisms.

• Asian-Australasian Journal of Animal Sciences
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• 제33권7호
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• pp.1103-1112
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• 2020

Objective: To measure whether a microbial additive could effectively improve the fermentation quality of delayed-sealing (DS) silage, we studied the effects of inoculants of lactic acid bacteria (LAB) and cellulase enzyme on microbial populations, ensiling characteristics, and spoilage loss of DS silage of Napier grass in Africa. Methods: Quick-sealing (QS) and DS silages were prepared with and without LAB (Lactobacillus plantarum) inoculant, cellulase enzymes, and their combination. The QS material was directly chopped and packed into a bunker silo. The DS material was packed into the silo with a delay of 24 h from harvest. Results: In the QS silage, LAB was dominant in the microbial population and produced large amounts of lactic acid. When the silage was treated with LAB and cellulase, the fermentation quality was improved. In the DS silage, aerobic bacteria and yeasts were the dominant microbes and all the silages were of poor quality. The yeast and mold counts in the DS silage were high, and they increased rapidly during aerobic exposure. As a result, the DS silages spoiled faster than the QS silages upon aerobic exposure. Conclusion: DS results in poor silage fermentation and aerobic deterioration. The microbial additive improved QS silage fermentation but was not effective for DS silage.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1717-1725
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• 2013

Traditional soybean paste from Shandong Liangshan and Tianyuan Jiangyuan commercial soybean paste were chosen for analysis and comparison of their bacterial and fungal dynamics using denaturing gel gradient electrophoresis and 16S rRNA gene clone libraries. The bacterial diversity results showed that more than 20 types of bacteria were present in traditional Shandong soybean paste during its fermentation process, whereas only six types of bacteria were present in the commercial soybean paste. The predominant bacteria in the Shandong soybean paste were most closely related to Leuconostoc spp., an uncultured bacterium, Lactococcus lactis, Bacillus licheniformis, Bacillus spp., and Citrobacter freundii. The predominant bacteria in the Tianyuan Jiangyuan soybean paste were most closely related to an uncultured bacterium, Bacillus licheniformis, and an uncultured Leuconostoc spp. The fungal diversity results showed that 10 types of fungi were present in the Shandong soybean paste during the fermentation process, with the predominant fungi being most closely related to Geotrichum spp., an uncultured fungal clone, Aspergillus oryzae, and yeast species. The predominant fungus in the commercial soybean paste was Aspergillus oryzae.

• 한국식품위생안전성학회지
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• 제28권4호
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• pp.306-311
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• 2013

본 연구는 부패미생물의 종류와 차이를 알아보기 위해 유기농산물과 일반농산물(깻잎, 양배추, 상추)을 구입하여 $4^{\circ}C$에 14일 저장한 후 일반목적배지를 사용하여 미생물을 분리 및 16S rRNA sequencing방법을 이용하여 동정하였다. 유기농산물 깻잎, 양배추, 상추의 총균수는 $5-7{\log}_{10}CFU/g$ 수준이었고, 일반농산물의 총균수는 $5-8{\log}_{10}CFU/g$ 수준이었다. 유기농산물보다는 일반농산물이 총균수를 더 많이 내재하고 있으나 유의적인 차이는 나타나지 않았다(p > 0.05). 유기농산물 깻잎에서 발견된 주요 균은 Microbacterium sp.이었으며, 일반농산물 깻잎에서 발견된 주요균은 Stenotrophomonas maltophilia이었다. 또한, 유기농산물에서 부패를 일으킬 수 있는 균인 Klebsiella pneumonia가 발견되었으며, 일반농산물보다 유기농산물에서 발견된 균의 종류가 더 많은 것을 확인할 수 있었다. 이에 본 연구 결과는 부패미생물에 대한 이해를 높이고 농산물의 신선도 및 유통기한을 늘리기 위한 새로운 살균소독제 및 부패 억제제를 개발하는데 좋은 기초자료로 사용될 수 있을 것으로 사료된다.