• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.85-94
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• 2022

To detect anomaly signs of thermal runaway in advance, this study analyzed the signals from various sensors installed in lithium-ion batteries. The thermal runaway mechanism was analyzed, and measurement variables for anomalies of a battery cell were surface temperature, strain, and gas concentration. The changes and characteristics of three variables during the thermal runaway process were analyzed under the abuse environment: the overheat and the overcharge. In experiment, the thermal runaway of the battery proceeded in the initial developing stage, the outgassing stage, and the ignition stage. Analysis from the measured data indicated that the suitable variable to detect all stages of thermal runaway is the surface temperature of the battery, and surface strain is alternative.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.188-189
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• 2019

본 논문은 리툼이온 배터리의 화재로 이어질 수 있는 전기적 위협(Electrical abuse) 상황 중 외부단락 상황을 재현하였다. 배터리의 초기 온도상태(60℃, 50℃, 25℃, 15℃)와 외부단락 상황에서 배터리의 최대 발열량과의 상관관계를 분석하였다. 초기온도 60℃ 보다 50℃에서 가장 큰 발열량을 보였다. 초기온도 60℃에서 더 큰 단락전류가 측정되었으나 전류가 인가되는 시간은 50℃에서 더 길어 단락실험간 최대 발열은 온도상태 50℃에서 최대 온도 117℃로 가장 크게 측정되었다.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.722-729
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• 2010

The aim of this study was to evaluate the physico-chemical, sensory, and microbiological properties of ready-to-eat Korean traditional seasoned beef ribs ("galbi-jjim") prepared by sous-vide/cookchill technology during storage at three different temperatures (4, 10, and $20^{\circ}C$). Beef short ribs marinated in soy sauce for 24 h at $3^{\circ}C$ were packed with vegetables under vacuum. Vacuum-packed beef ribs mixed with vegetables were heated at $90^{\circ}C$ for 90 min in a water bath, and then immediately chilled below $3^{\circ}C$ within 120 min in an ice slurry. Physicochemical (pH, water activity, TBARS, $L^*a^*b^*$ color, and texture profile), sensory (appearance, odor, flavor, texture, and acceptance) and microbiological (Coliform, Escherichia coli, food-borne pathogenic bacteria) properties of the samples were determined during storage at different temperatures. Results showed that pH, $a_w$, and sensory evaluation of products were not affected in any consistent way as a function of either storage duration or temperature. Coliform, E. coli and food-borne pathogens were not detected during storage at any temperature. However, TBARS significantly increased during storage period (p<0.05). Based on TBARS values, SV/CC "galbi-jjim" can be stored for 15 d, 12 d and 1 d at 4, 10 and $20^{\circ}C$, respectively.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.902-907
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• 2006

Freeze dried crude bacteriocin was encapsulated within an acid-soluble coating material, Eudragit EPO, using a surface modification technique through a hybridization system. The pH and titratable acidity of control yoghurt were 3.92 and 1.56%, respectively, after 24 hr of fermentation at $42^{\circ}C$, whereas yoghurt containing 500 AU/mL encapsulated bacteriocin exhibited a higher pH (4.37) and lower titratable acidity (1.2%). Yoghurt containing encapsulated bacteriocin had significantly lower titratable acidity when the duration of fermentation (to pH 4.5) and subsequent refrigerated storage ($4^{\circ}C$) was longer than 20 days. There were no significant differences in the viability of lactic acid bacteria after 15 hr of fermentation. This suggests that microencapsulated bacteriocin has the potential to control the excessive growth of yoghurt starters caused by temperature abuse or post-acidification.

• Korean journal of food and cookery science
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• v.30 no.5
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• pp.603-612
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• 2014

According to the microbiological standard, Staphylococcus aureus, Clostridium perfringens and Listeria monocytogenes should not be detected in milk and egg products in Korea. Refrigerated food such as milk must be kept under $10^{\circ}C$ at retail markets. However, temperature abuse of refrigerated foods at such markets is often observed. We compared the growth and survival kinetics of S. aureus and C. perfringens at 10 and $15^{\circ}C$, and the growth kinetics of L. monocytogenes at 4 and $10^{\circ}C$ in whole and skim milk and ready-to-eat (RTE) quail eggs to evaluate their growth possibilities at retail markets. Regardless of storage temperature, the level of S. aureus reached the maximum level ($10^8-10^9CFU/ml$) in whole milk, non-fat milk and RTE quail eggs within the expiration date. Even low contamination levels of S. aureus (10 CFU/mL) grew rapidly in milk and quail eggs to reach the maximum level within the shelf life. Survival of C. perfringens in whole milk was greater than that in non-fat milk, indicating that the fat content in milk influences the survival of C. perfringens. For L. monocytogenes, the population in milk increased by 0.5-1 log CFU/mL at $4^{\circ}C$, while the populations reached the maximum level at $10^{\circ}C$ within the expiration date, regardless of initial contamination levels. In quail eggs, L. monocytogenes grew to the maximum level within the expiration date (60 days) at both temperatures. S. aureus and L. monocytogenes must be controlled to be negative, and proper temperature management should be emphasized at retail markets to protect the consumer. Since C. perfringens did not grow in milk and RTE quail eggs, there is no risk due to the growth of C. perfringens in these products at retail markets.

• Journal of Dairy Science and Biotechnology
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• v.42 no.2
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• pp.64-76
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• 2024

This study analyzed the physicochemical properties and rheology of frozen condensed skim milk during thawing at 5 room temperature (20℃). The viscosity of the condensed milk was 80 cps (21.5℃) immediately after manufacture, and this value was decreased to 0 cps (21. 5℃) during storage at day 7. The particle sizes of the condensed skim milk were 0.128 mm just after manufacture, and 0.522 and 0.818 mm at days 3 and 5 of thawing at 20℃, respectively. Condensed skim milk with no temperature abuse had lower acidity than those stored at room temperature on the 3rd and 7th days. Additionally, a sandy texture was observed as the thawing period increased. Based on the comprehensive results of this study, when frozen condensed skim milk is added to a product as a raw material, the longer the thawing period at room temperature, the longer the ice crystals inside melt and become water drips. Quality defects, such as weight loss, decreased pH, protein denaturation, and texture deterioration, are expected to occur.

• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.38-43
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• 2018

A few authors have already investigated microbial contamination of leafy vegetables in distribution condition and examined the effect of temperature abuse on microbial safety or product quality. But this study analyzed proliferation of indicator microorganisms and food poisoning bacteria in real situation in Korean agroindustry and investigated washing effect of micobial contamination on leaf surface. Leafy vegetables were found to be contaminated with aerobic bacteria at $0.1{\sim}0.32{\times}10^3CFU/g$. Staphylococcus aureus and Bacillus cereus were detected in leafy vegetables at $0{\sim}0.54{\times}10^3CFU/g$. However, Salmonella spp., Coliforms, Clostridium spp. and Listeria spp. were not detected in any samples. Indicator microorganisms and food poisoning bacteria on leafy vegetables increased at room temperature when simulatively distributed condition. After clean-up, the indicator microorganisms and food poisoning bacteria of kimchi cabbage, lettuce and perilla leaf were decreased to a very low level. This study suggests that it is necessary to improve the level of hygiene management such as use of cold chain system and hygiene management of transport tools during the distribution process for fresh leafy vegetables.

• Analytical Science and Technology
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• v.19 no.2
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• pp.149-154
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• 2006

A gas chromatography-mass spectrometric method was developed for the determination of formaldehyde in urine and saliva. In a 20 mL glass tube, 0.2 mL of urine or saliva was taken. Further, 1.8 mL of 0.1 M HCl, 0.1 mL of 2,000 mg/L 2,4-dinitrophenyl hydrazine and $20{\mu}l$ of 500 mg/L acetone-$d_6$ as internal standard were added in the tube and sealed tightly with cap. The solution was shaken for 20 min at room temperature and extracted using 4 mL of toluene. The extract was concentrated and redissolved with $100{\mu}l$ of acetonitrile, and then measured by gas chromatography-mass spectrometer (selected ion monitoring). The detection limit was 2.0 ng/mL and 0.5 ng/mL in saliva and urine, respectively. The calibration curves showed good linearity with r = 0.997 and 0.998 for saliva and urine, respectively. The method was used to analyze formaldehyde in rat urine after oral exposure. The developed method may be use ful to the monitoring for formaldehyde exposure in human.

• Food Science of Animal Resources
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• v.27 no.2
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• pp.185-189
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• 2007

Animals must be inspected prior to and after slaughter to make certain they are free of diseases and unacceptable defects. Since meats are potentially hazardous foods, they should not be accept if there are any signs of contamination, temperature abuse, or spoilage. This survey was aimed to monitor the current situation of country-of-origin labels and sanitation for the meat markets in Seoul, Korea. The markets were divided into groups as to 25 territories in Seoul and the size of markets (large size, medium size, and small size). In terms of size distribution, small butcher shops occupied the highest percentage. On the itemized suitability test of unpacked and packed beer in Seoul, most butcher shops showed good evaluation. However, labels indicating the grade, storage and cooking instruction for unpacked beef were not properly posted on the products. The results of monitoring sanitation conditions for butcher shops in Seoul showed relatively low suitability. Especially, there were serious lack of knowledge about wearing the sanitation clothings, caps, and shoes. The problem with food safety is so complicated that producers, consumers, merchandisers, the press, the government and the scholar should try to solve the problems altogether. Also, it is important to educate and provide them with correct understanding and information for food hygiene and safety.