• Food Science and Biotechnology
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• v.14 no.6
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• pp.752-757
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• 2005

Changes in milk quality during storage of extended shelf life milk (ESL milk) and non-ESL milk were evaluated. No significant differences were observed between ESL and typical ultra high temperature-treated (UHT) milk in physicochemical properties including non-casein nitrogen (NCN) content, whey protein nitrogen index (WPNI), and L-ascorbic acid content. Low temperature and long time-treated milk (LTLT milk) had significantly higher NCN content and WPNI than those of UHT milk. In terms of microbial quality, yeast, molds, coliforms, and other bacteria were not detected in ESL milk during entire storage (21 days after expiration date) period at 4 and $25^{\circ}C$, while LTLT milk was more susceptible to microbial infection. Rats fed ESL milk resulted in significantly higher body weight, average daily gain, and feed efficiency than those given UHT milk. These results suggest ESL milk maintains better microbial quality than typical UHT milk, particularly during storage under extended refrigeration and at high temperature.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.257-268
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• 2016

Physiological characteristics of five new apple cultivars from the Korean apple breeding program were evaluated as a function of harvest time and storage after harvest. Internal ethylene concentration (IEC), flesh firmness, soluble solids concentration (SSC), and titratable acidity (TA) were measured in 'Summer Dream', 'Summer King', 'Green Ball', 'Picnic', and 'Hwangok' apples at harvest, during shelf life at $20^{\circ}C$, and one day after cold storage at $0.5^{\circ}C$ in air. IEC increased during shelf life in 'Summer Dream', 'Summer King', and 'Green Ball' but not in 'Picnic' or 'Hwangok', regardless of harvest time. Flesh firmness decreased towards harvest time and decreased gradually with time in cold storage only in the former three cultivars. In turn, IEC increased during cold storage in the first three cultivars but not for the last two cultivars, irrespective of harvest time. Changes in SSC and TA did not consistently relate to harvest time or storage period but TA tended to decrease as IEC increased. Furthermore, IEC was negatively correlated with flesh firmness except in the 'Green Ball' cultivar but the significance level was much greater in 'Summer Dream' and 'Summer King' (p < 0.0001) than in 'Picnic' (p < 0.01) or 'Hwangok' (p < 0.05) cultivars. Flesh firmness was positively correlated with TA in the first three cultivars but not in the last two cultivars. Overall, the results indicate that cultivars for which IEC increased after harvest had reduced flesh firmness and TA after storage.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.999-1006
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• 2004

The selective media including NPC agar, DHL agar, MacConkey agar, and Cetrimide desoxycholate agar were compared to determine selectivity for the growth of bacteria Cetrimide desoxycholate agar was better than NPC agar, DHL agar, and MacConkey agar for the growth of psychrotrophic grarn-negatve bacteria including Pseudomonas. and for the inhibition of gram positive bacteria The specificity of resazurin reduction time test was investigated to determine post-pasteurization contamination of market milk. Equal volume of Cetrimide desoxycholate broth was added to market milk, which was then incubated at $21^{\circ}C$ for 18 hours. The growth of bacteria in the incubated milk was detected in resazurin reduction time test. The results in resazurin reduction time test and total bacteria number count of market milk after storage at $7^{\circ}C$ were relatively correlated each other. Pseudomonas was isolated most frequently from the market milk stored at $7^{\circ}C$ for 10 days, and Acinetobacter and Aeromonas followed. Acinetobacter, Pseudomonas and Enterobacter were frequently isolated from the mixture of market milk and Cetrimide desoxycholate broth incubated at $21^{\circ}C$ for 18hours in resazurin reduction time test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.700-707
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• 2016

Recently, ammunition malfunctions of the 40mm grenade were reported during live fire training. When 72 40mm grenades were fired by the army, 11 duds were encountered. The dud ammunition rate was approximately 15%. Because ammunition is used a long time after its manufacture, it is necessary to ensure its performance after long-term storage. In this study, we attempted to decrease the dud ammunition rate of 40mm grenade (K200) fuzes through quality improvement. First, it was determined by the detonator performance test that abnormal explosions occurred due to the degradation of the detonator as a result of its aging characteristics. Second, we improved the fuze quality of the 40mm grenade. Third, we tested its shelf life to estimate its life expectancy. The shelf life of the 40mm grenade fuze obtained using the Arrhenius equation was 6.5 years for the existing grenade fuze and 45.5 years for the improved grenade fuze. This showed that the shelf life of the improved grenade was increased approximately 7 times. Therefore, the improved 40mm grenade fuze contributes to the quality improvement of the 40mm grenade by decreasing the dud ammunition rate during long term storage.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.17-25
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• 2014

The purpose of this paper is to present a method to estimate the storage life of propellant bag for degradation of breaking load with storage time by using gamma process model. The nitrogen compound generated by natural decomposition of propellants degrades the breaking load of propellant bag with time. The statistical distributions of condition and lifetime with time were shown from the results of accelerated life test of propellant bag cloth at $80^{\circ}C$. It was found that the use of median for life was highly appropriate and the $B_1$ or $B_5$ life should be selectively applied to the quality assurance policy.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.310-316
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• 2017

This study was analyzed the effects of boron (B), calcium (Ca), silicon (Si) on quality and shelf life of 'Unicorn' cherry tomato at the light red maturity-stage. The storage conditions were modified atmosphere packaging (MAP) by oxygen transmission rate (OTR) packaging film at $5^{\circ}C$, $11^{\circ}C$, and $24^{\circ}C$. Respiration and ethylene production were the lowest in B + Ca + Si -treated tomato fruits. The lowest fresh weight loss and the longest shelf life resulted from the B + Ca + Si treatment. And the firmness was enhanced by B + Ca + Si treatment at harvest time, and it was retained after storage at $5^{\circ}C$, $11^{\circ}C$, and $24^{\circ}C$. Significantly lower soluble solids, lycopene, and color development were found at B + Ca + Si-treated tomato fruits compared with control after storage. Moreover, the highest titratable acidity and vitamin C content were observed in B + Ca + Si-treated tomato fruits after storage. From the above results, it was concluded that B + Ca + Si combined treatment can delay the maturity of cherry tomato after harvesting, and retained the firmness and prolong the shelf life.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.252-260
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• 1985

The changes of the qualities and the components of 5 different Takju (Korean wine) in various stroage temperatures were evaluated. Commercial Takju didn't change in acidity and alcoholic degree at $5{\sim}10^{\circ}C$ for 36 hours. But at $30{\sim}35^{\circ}C$ the alcohollic degree has inversed to $5.0{\sim}7.0$. As time went by, pH nearly went down to pH 3.7 and went up back over 4.0. Amino acidity was risen continuously during the stroage terms and the change of reducing sugar was irregular. The number of vegetable cell of yeast in commercial Takju at $30{\sim}35^{\circ}C$ after 18 hours was $2.4{\times}10^8$, at $5{\sim}10^{\circ}C$ after 36 hours $2.4{\times}10^8$, and each of them was reduced below $1{\times}10^8$ after exceeding the limit of shelf-life. Number of general bacteria was increased suddenly in a high temperature at the first and it was decreased afterwards, but the tendency of increase and decrease was slow in a low temperature. It was possible to keep the quality for 5 days at $5{\sim}10^{\circ}C$ in case of commercial Takju and the shelf-life of pasteurized Takju was extended over 7 days.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.306-310
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• 1991

A simplified mathematical model to estimate changes in total acidity of Chinese cabbage kimchi during fermentation was developed as a function of temperature and salt concentration. Assuming that tolerable acceptability reached at 0.75% total acidity, the shelf-life of kimchi was predicted by the model. The predicted value was in good agreement with the actual shelf-life measured by organoleptic tests.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1087-1092
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• 2000

Traditional food soybean curd was prepared using the fresh fruit juice of Schizandra chinensis RUPRECHT(Omija) and Prunus mume(maesil), and investigated the optimal preparative conditions(water addition ratio, heating time of mashed soybean and fresh fruit juice concentration), physical properties, sensory evaluation and shelf-life. Soybean curd coagulated with 0.9% Omija juice showed the highest yield at $85^{\circ}C$, 12.5 times water addition and 5 min heating. For soybean curd coagulated with 1.5% Maesil juice showed the highest yield at $85^{\circ}C$, 10 times water addition and 5 min heating. The physical properties (hardness, adhesiveness, chewiness and gumminess) of soybean curd coagulated with juices of Omija and Maesil showed lower values for hardness, adhesiveness, chewiness and gumminess. However sensory scores of both were evaluated higher than those of coagulated with $CaSO_4$. The shelf-life of soybean curd prepared from Omija and Masil juices and then soaked in 0.1% acetic acid was better than that of coagulated with $CaSO_4$ or soaked in distilled water.

• Food Science and Preservation
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• v.24 no.3
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• pp.343-350
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• 2017

Effects of high pressure processing on physicochemical and microorganisms properties in birch sap were investigated using variable high pressure processing conditions. The viable cell counts of untreated birch sap was 4.0 log CFU, whereas high pressure processed sap were not detected. In birch sap was treated with 450 to 550 MPa, microorganisms were not detected during storage period, and physicochemical properties as well as color were slightly changed. The more processing time and pressure, its quality variations were more stable and then its optimum processing condition was determined with 120 sec at 550 MPa. The microorganisms and physicochemical properties of treated birch sap were investigated during storage at $5^{\circ}C$ and $10^{\circ}C$ for 45 and 28 days. Changes of physicochemical properties of treated birch sap were smaller than those of the untreated, but viable cell count were not detected during storage period. As for pH, $^{\circ}Brix$, and turbidity result of birch sap, quality shelf life of control and treatment were 4 and 24 days, respectively. Especially, ${\Delta}E$ value of instrumental color was untreated birch sap 4 days similar with the high pressure processed it for 28 days. These results indicated that the high pressure processing can be used as an effective method to improve the shelf life of birch sap.