• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.343-349
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• 1987

This study was executed to investigate proper storage conditions for freshness of lunch-box and prevention of lunch-box borne illness. When boiled rice was put into the empty lunch-box without cooling, temperature of the lunch-box was $70^{\circ}C$ to be able to destroy vegetative cell of microoganism in the lunch-box. Temperature of the side-dish canister that is placed on the hot lunch-box was increased from $15^{\circ}C$ to $53^{\circ}C$. The use of the insulator(one to two layer) between the lunch-box and side-dish canister was effective in insulation of the heat that is conducted from the hot lunch-box to the side-dish canister. The insulation layer(asbestos) was also effective to inhibit the decrease of pH value and growth of microoganisms in the toiled rice and side-dish during storage of the lunch-box. The number of microoganisms in the lunch-box covered without cooling was less than in the case of lunch-box covered after cooling; however, the amount of generation in condensed water that is responsible for swelling of boiled rice in the lunch-box occurred much more in the one than in the other, and was a little generated in the case of high temperature storage, insulator use, and when covering the lunch-box after cooling, and pre-evaporation by stirring boiled rice in the cooking pot before filling it. In addition, inserting the heat insulators on and bottom of the lunch-box the boiled rice can be eaten without coldness in winter season.

• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.199-204
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• 2019

This study aimed to generate a probability distribution model based on temperature data of frozen food storage facility as input variables for microbial risk assessment (MRA). We visited 8 food-handling businesses to collect temperature data from their cold storage warehouses. The overall mean temperature inside the storage facilities was $-20.48{\pm}3.08^{\circ}C$, with 20.4% of the facilities having above $-18^{\circ}C$, with minimum and maximum temperature values of -10.3 and $-25.80^{\circ}C$ respectively. Temperature distributions by space locations of natural and forced convection were $-22.57{\pm}0.84$ and $-17.81{\pm}1.47^{\circ}C$, $-22.49{\pm}1.05$ and $-17.94{\pm}1.44^{\circ}C$, and $-22.68{\pm}1.03$ and $-18.08{\pm}1.42^{\circ}C$ in the upper (2.4~4 m), middle (1.5~2.4 m), and lower (0.7~1.5 m) shelves, respectively. Probability distributions from the temperature data were obtained using the program @RISK. Statistical ranking was determined using goodness of fit to determine the probability distribution model. Our results show that a log-normal distribution [5.9731, 3.3483, shift (-26.4281)] is most appropriate for relative MRA conduction.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.4
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• pp.326-332
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• 2021

Swabs are useful and common sampling tools in various research fields, such as medicine, ecology, biotechnology, forensic medicine, and pollutant monitoring systems. Collection reagents are one of the essential components in sampling. It is important to develop a sample collection kit and designate an appropriate storage temperature because samples need to be stored for a long time. The purpose of this study was to identify the effects of three collection reagents and three storage temperatures on the recovery of living bacteria without media. We selected Escherichia coli and Staphylococcus aureus as representative environmental bacteria. Distilled water (DW), phosphate buffered saline (PBS), and Tris-EDTA (TE) buffer were used as collection reagents and stored at 22℃, 4℃, and -70℃ after sampling. The results of using each collection reagent and storage temperature on the bacteria were compared using relative light units (RLU) and the number of colony forming units (CFU). When using -70℃ storage temperature and the TE buffer, the number of living bacteria and the RLU values remained constant. It is therefore recommended that the sample be stored at -70℃ immediately after collection and a TE buffer solution be used as the collection reagent.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.381-389
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• 2004

To investigate changes of multi-purpose solutions for soft contact lens(MPS) depending on using period or keeping temperature, we evaluate four brands of MPS. No significant difference was seen in protein deposit removing efficacy after samples had used for 24 weeks and kept at $4^{\circ}C$, $20^{\circ}C$ or $30^{\circ}C$. The pH values of the samples of 4 brands measured weekly over the 24 week testing period. The initial average pH value of samples were 7.0, 7.5, 7.6 or 8.2. One brand of MPS was in the range of the threshold for ocular awareness, which is outside the zone of 6.6 ~ 7.8. During the testing period, the pH value were decreased in using period-dependent manner. At the 24th week, the average pH values of samples turned to 6.6, 7.2, 7.2 or 7.7. However, the difference of keeping temperature was not associated with decreased levels of pH values. After 24 weeks, one of total 36 samples was contaminated by bacteria. Furthermore, the change of components was shown after 24 weeks in the analysis using thin layer chromatography and the analysis of UV absorption pattern. The results of our study provides that the keeping temperature of MPS is not the important factor of changes of MPS, but the using period of MPS can cause contact lens wearers discomfort.

• Fire Science and Engineering
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• v.27 no.2
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• pp.70-74
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• 2013

It is very important for the collected samples at fire scenes to be properly preserved for laboratory analysis. Preserving abilities of four type containers, metal cans, glass jars, zipper and heat sealed polymer bags, with the five ignitable liquids (toluene, n-octane, o-xylene, n-decane and n-hexadecane) were examined with gas chromatography-mass spectrometry. The glass jars with Teflon (PTFE) liner were the best ability to prevent the evaporation of the ignitable liquids.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.29-33
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• 2021

Purpose Plasma renin activity (PRA) test is important for the diagnosis of primary aldosteronism. PRA is an easily deformed substance in vitro and affected by temperature changes. Laboratory of ASAN medical center has consistently found that there was a difference between the initial and re-experimental results. We compared and analyzed the differences in PRA test results according to the sample storage status. Materials and Methods The measurement of PRA was performed by using the radioimmunoassay. From August to September 2020, 43 PRA re-test samples were tested with different sample storage condition. The first group was re-examined by freezing the plasma-separated samples at -18℃, and the second group was re-examined with refrigerated EDTA sample. Also, additional tests were conducted on 13 PRA samples to verify the effect on thawing temperature differences in plasma-separated samples. The same samples were divided into two parts and stored frozen at -18℃, respectively, and thawing samples in room temperature and those in refrigerator were were conducted. Each result was compared and analyzed based on the initial experimental results. Results The results of re-examination after frozen storing plasma separation samples showed a lower correlation than the results of re-examination with EDTA plasma samples in refrigerator. When calculating the percentage based on the initial test results, the average percentage of each was 404.9% and 133.8%. The correlation coefficient was also R=0.8501 and R=0.9966, respectively, showing a higher correlation between plasma in the refrigerated sample EDTA tube. In comparison experiments with differences in thawing temperature, average percentage of the results of initial test and room temperature thawing was 94.3% and the average percentage of the results of refrigerated thawing was 88.0%. After again freezing the sample, the average percentage of the second room temperature thawing result is 107.5%, and the second refrigerated thawing group is 112.7%. Both groups showed an increase from first thawing. Conclusion A comparative analysis of retesting according to differences in sample storage methods in PRA tests showed a higher correlation between the results of retesting of the refrigerated EDTA plasma. And repeated freezing and melting of plasma separation samples, regardless of temperature during defrosting, has been shown to affect results. Therefore, retest of PRA should re-collect plasma from original EDTA plasma to increase reproducibility.

• The Hankook-Saengyark Bo
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• no.226
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• pp.5-5
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• 1998

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.422-427
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• 2015

This study was carried out to investigate the microbiological contamination levels of Dutch coffee products marketed in Korea. The temperature conditions during distribution and storage were also considered in this experiment. Retailed Dutch coffee were purchased from regional cafes, that is, these were self-blended by the cafes, and the marketed products were purchased from department stores and from Internet sites. The 21 samples were blended in a coffee house and 9 were obtained from department stores or were delivered from internet sites. House blended Dutch coffee contained $35.2{\pm}15.8CFU/mL$ of general bacteria, and this increased to $78.4{\pm}29.7CFU/mL$ at room temperature or $51.2{\pm}32.1CFU/mL$ after refrigeration for 5 days. These almost reached the highest criteria level for the Korea Food Sanitation Law. After 10 days, the count increased to $98.5{\pm}58.4CFU/mL$ at room temperature and $86.7{\pm}44.2CFU/mL$ at refrigeration temperature. In the Dutch coffee for distribution, $39.6{\pm}20.1CFU/mL$ of general bacteria were detected, but these did not increase after 5 days or 10 days both for room temperature and under refrigeration. The Coliform group was not found in any kind of Dutch coffee, and Fungi was founded in 60% of the Dutch samples purchased in coffee houses, department stores, and shopping sites mall. On day 0 day, $2.6{\pm}1.7CFU/mL$ of fungi were detected in the coffee house Dutch, and it did not increase significantly during the storage period at room and in a cold temperature. $3.5{\pm}3.4CFU/mL$ of fungi were detected in the Dutch coffee for distribution, and it didn't increase during further storage under any temperature.

• Membrane Journal
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• v.22 no.5
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• pp.301-308
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• 2012

Phosphazene diagnostic membranes were prepared to measure blood glucose level of diabetics. Final absorbances at 680nm through activated phosphazene membranes were measured at various temperature and humidity by varing concentration of glucose in blood. Measuring temperature and humidity did not seriously affected the end-point results of varing absorbance values as time (K/S). The effects of storage temperatures on the measurements of glucose concentration were studied after activated phosphazene diagnostic membranes were stored at various temperatures for 3 days, 1 week, 3 weeks, and 5 weeks. The stabilities of phosphazene dianostic membranes were confirmed even at RH 80%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.277-281
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• 1997

The cell density changes of Vibrio mimicus K-1 in sea water and arkshell feeding it were examined at various temperature. The strain was suspended in sterilized sea water and storaged at experimental temperature $(5,\;10,\;15,\;20,\;and\;28^{\circ}C)$). At intervals of up to 10 days, aliquots of each suspension were plated onto BHI agar. At 5 and $10^{\circ}C$, the plate counts of V. mimicus K-1 showed a rapid decline, which 3s known to be a reault of this bacterium's entering into the viable but non culturable state. At 20 and $28^{\circ}C$, however, V. mimicus K-1 are stable over the 10 days experimental periods. V. mimicus K-1 was fed to arkshell, which was subsequently stored at temperatures ranging from 5 to $20^{\circ}C$ for 10 days. The samples of arkshell were homogenized and plated at intervals to determine the cell density of V. mimicus K-1 and total aerobic population of bacteria present. At 5 and $10^{\circ}C$, the numbers of V. mimicus K-1 in sea water rapid decreased over the 10 days experimental periods. However, little change of V. mimicus K-1 density was observed in shellstock arkshell at 5 and $10^{\circ}C$. While, V. mimicus K-1 density was decreased more rapidly to level below limit of dectection in shucked arkshell at same temperature. Incubation at the higher temperature $(20^{\circ}C)$ resulted in large increase in total aerobic bacterial number of shellstock arkshell. These results suggest that even with proper storage, indigenous levels of V. mimicus may remain sufficiently high in shellstock arkshell to produce infection in compromise hosts.