• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.916-923
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• 1998

To provide more information on the enteric pathogen Campylobacter jejuni in the view of food sanitation, survival characteristics of two strains of C. jejuni in the different conditions were investigated. When $10^7{\;}or{\;}10^3{\;}per{\;}ml$ of C. jejuni cells were inoculated in the supplemented Brucella broth and kept at $42^{\circ}C,{\;}25^{\circ}C{\;}and{\;}5^{\circ}C$ under the static aerobic condition for 7 days, organisms exponentially proliferated to $a{\;}>10^8$, even in the $10^3{\;}per{\;}ml$ inoculated-sample at $42^{\circ}C{\;}for{\;}1{\sim}2{\;}days$ and the considerable level of viability maintained during 7 days. At $5^{\circ}C$, most of the initial level of organisms survived at the early period and only $a{\;}<{\;}0.5-log_{10}$ cells decrease were observed during the 7 days. At $25^{\circ}C$, a remarkable number of C. jejuni declined within $1{\sim}2{\;}days$ and showed undetectable level of cells after 4 days. When sterile milk and minced chicken meat were artifically inoculated with $10^7{\;}per{\;}ml$ of C. jejuni, mostly, a $1-to{\;}2-log_{10}$ count decrease occurred at $42^{\circ}C{\;}and{\;}5^{\circ}C$ while $a{\;}>3{\;}log_{10}$ decrease at $25^{\circ}C$ during 7 days. Unexpectedly, no colonies appeared on the plate inoculated from the minced chicken meat sample kept at $42^{\circ}C$ after 4 days. The results suggest that C. jejuni contaminated to food can survive at the refrigeration temperature whereas they are sensitive to at the room temperature. Also, it is shown that the growth of C. jejuni at the optimal temperature may vary to the food sources.

• Journal of Life Science
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• v.25 no.10
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• pp.1124-1131
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• 2015

Consumer interest in the stability of medicinal herb extracts during storage has increased. Although the advent of new technologies has improved preservation conditions, increasing the storage time, there are few studies on the preservation of herb extracts. The purpose of this study was to perform microscopic observations of Samul-tang decoctions under various preservation conditions. The storage temperature (a high temperature, room temperature, with or without light, refrigeration, or cryopreservation) and storage time (0, 15, 30, 90, and 180 days) were given to each condition Macroscopic morphology, pH, UV absorption, HPLC, and bacteriological studies were performed to determine microscopic changes in Samul-tang decoctions. The biological activity (tyrosinase inhibition) of the Samul-tang decoctions was also examined. There were no major changes in the indicated observation items when the extracts were stored in each condition. However, at higher storage temperatures and longer storage times, microscopic changes increased, although no bacteria were detected. Furthermore, the higher the storage temperature was and the longer the storage time was, the bigger the change was, despite of minor microscopic changes. Therefore, to maintain the stability of herbal extracts during storage, it is recommended to keep the Samul-tang decoction in the preservation condition of refrigeration and cryopreservation or without light rather than high temperature and room temperature as possible.

• Journal of Food Hygiene and Safety
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• v.31 no.5
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• pp.365-374
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• 2016

This study was carried out to investigate the effect of vinegar on pH, total bacterial count, texture and color of rice with vinegar before and after storage at $4^{\circ}C$ and $25^{\circ}C$. This results obtained were summarized as follows : The pH value and total bacterial counts were not significant changed under different storage conditions with sushi vinegar, but control without sushi vinegar was increased the number of bacteria from storage 1 days. and When rice with vinegar was stored at low temperature ($4^{\circ}C$), the tendency of textural changes such as hardness, springiness, cohesiveness, chewiness, brittleness and adhesiveness was almost the same as those of $25^{\circ}C$. However, the rate of change was much higher in rice with vinegar when stored at $4^{\circ}C$ than at $25^{\circ}C$. and The Hunter's color parameters such as L, a, and b, of rice with vinegar were not changed much during storage at both $25^{\circ}C$. However, L value was slightly increased during storage, but a value was increased negatively without changing b value of rice with vinegar during storage at $4^{\circ}C$.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.530-536
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• 2010

This study was the tenderizing activity of fig and kiwifruit using meat cooking. Furthermore, the effects of various seasonings and flavor spices were investigated. The proteolytic activity of kiwifruit was 36,513 uM/g fruit, whereas that of fig was 24,131 uM/g fruit. The best amount of fruit for meat cooking was 3~5% for kiwifruit and 5% for fig among three different dilutions, 3%, 5% & 10%. The effect of fruit ratio showed that treatment with 'kiwifruit only' produced the best organoleptic results, and there was no significant difference between the kiwifruit and fig ratios, 3:0, 2:1, 1:1. The best marinating time for meat tenderizing by fig and kiwifruit was 6hr at $4^{\circ}C$. The best marinating temperature for meat tenderizing by fig and kiwifruit was $25^{\circ}C$ rather than $4^{\circ}C$. Fruit sauce containing basic seasonings such as soy sauce, sugar, oligosaccharides, and sesame oil had a pH of 4.64 for fig and 4.23 for kiwifruit. The addition of soy sauce, oligosaccharides, and rice wine decreased the proteolytic activity of the fruits. Fruit sauce containing basic seasonings, garlic, ginger, onion and scallion had a pH of 4.71 for fig and 4.43 for kiwifruit. Finely chopped garlic, finely chopped scallion, and pureed onion, finely chopped ginger, and pear juice, all increased the proteolytic activity of the fruits. There the fruit sauce containing seasonings and flavory spices for meat cooking improved the tenderness and preference in terms of sensory evaluation without undesirable taste or increased fruits.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.814-818
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• 1994

Control system for both rapid fermentation and storage of yogurt in refrigerator was developed and its performance was investigated. Fermentation temperature for normal and Bifidus containing yogurt was maintained at maximum $40^{\circ}C$ for about 7 and 11 hours, respectively. The pH, acidity, total viable cell number of lactic acid bacteria and viscosity of both yogurts after completing the fermentation were $4.23{\sim}4.29$, $0.93{\sim}0.97%$, $4.8{\times}10^7{\sim}$2.54{\times}10^8\;cfu/ml$ and $1,700{\sim}1,810\;cp$, respectively. The rate of fermentation for normal yogurt was faster than that of Bifidus yogurt. The changes of pH, acidity, viable cell number and viscosity during storage time were $4.09{\sim}4.54$, $0.76{\sim}1.1%$, $9.4{\times}10^6{\sim}5.68{\times}10^8\;cfu/ml$ and $1,450{\sim}2,000\;cp$, respectively. Yeast and fungi were not nearly detected during storage time for both yogurts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.136-140
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• 1986

The change of cell counts of Vibrio parahaemolyticus in fish muscle by the storage time and temperature was examined to get basic informations for precautionary steps against food poisoning of slices of raw fish (sashimi). There fore, we inoculated fish homogenate of oceanic bonito (Katsuwonus pelamis), yellow tail (Seriola quinqueradiata) with Kanagawa positive Vibrio parahaemolyticus and stored it at $30^{\circ}C,\;18^{\circ}C,\;4^{\circ}C\;and\;-20^{\circ}C$ for 24 hours. The number of the Vibrio parahaemolyticus upon fish homogenate stored at $30^{\circ}C\;and\;18^{\circ}C$ decreased for the first two hours and increased thereafter. When the fish homogenates inoculated with Vibrio parahaemolyticus at about $10^3$ per gram were stored at $18^{\circ}C\;and\;30^{\circ}C$ for 10 hours, the cell numbers increased about 10 times and 1,000 times initial cell numbers, respectively. The survival rate of Vibrio parahaemolyticus was about $20\%$, when the inoculated fish homogenates were stored at $-20^{\circ}C$ for 24 hours. Vibrio parahaemolyticus inoculated in fish homogenates was decreased by about $10\%$ of initial cell numbers by the storage at $4^{\circ}C$ for 4 hours and it was decreased by about $50\%$ after 24 hours storage of the samples at the same temperature. The decreasing rate of inoculated Vibrio parahaemolyticus in fresh fish muscle homogenate was higher than that in frozen fish muscle homogenate during the storage time at a refrigerator.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.241-245
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• 1995

Focusing on quality problems of delayed chilling porcine muscle, the effects of delayed chilling and aging on the contents of ATP-related compounds and taste of pork were investigated. Twelve Landrace pigs were employed and bisected: left sides were delay-chilled(DC) at room temperature($20^{\circ}C$) for 3 hrs, whereas right sides were conventionally chilled(CC). ATP-related compounds tested were adenosine triphosphate(ATP) and its derivatives in pork muscle, inosine monophosphate(IMP), guanosine monophosphate(GMP) and L-glutamate in cooked broth. DC sides showed more rapid pH decline and degradation of nucleotides than did CC sides. The levels of ATP and adenosine monophosphate(AMP) were not changed significantly. However, adenosine diphosphate(ADP) and IMP showed the highest levels at the 1st and 5th day, respectively. Hypoxanthine(Hx) was gradually increased(p<0.05) during aging. During aging, the IMP contents cooked broth tended to decrease, while the GMP and L-glutamate contents increase. As a result of these, the taste score got better and finally the results of sensory evaluation became increased(p<0.05). However, compared to CC sides, DC sides did not seem to lower taste of pork.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.199-203
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• 1994

Software for refrigerator capable of both rapid fermentation and suitable storage of Kimchi was developed and its performance was investigated. Refrigerator system consists of an insulated fermentation room, heater, damper for the control of outer cold air and two sensors for recognizing temperature of heater and fermentation room, which control temperature and time period of affecting Kimchi fermentation. Effects of fermentation at different NaCl concentration and three fermentation function keys were studied; At key I, time which was elapsed to edible ripening state, pH 4.5 and total acid 0.6%, was about $3{\sim}4$, $4{\sim}5$ and $11{\sim}12$ days, respectively. At key II, time was about $2{\sim}3$, $3{\sim}4$, and $10{\sim}11$ days, and at key III, about 2, 3 and $9{\sim}10$ days, respectively. Effect of storage at three fermentation function keys was all maintained to the level of a palatable pH range until 14 days. Sensory evaluation of Kimchi showed also significant difference in a taste.

• Journal of Life Science
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• v.14 no.4
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• pp.664-669
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• 2004

The contamination of Bacillus cereus was investigated in 240 RTE (ready-to-eat) food samples including 118 seafoods, 82 Korean packaged meals and 40 other RTE foods. Many B. cereus presumptive strains were isolated from the enrichment culture in Tryptic Soy Broth (TSB) added polymyxin, followed by selective culture in Mannitol Egg Yolk Polymyxin (MYP) agar and Gram staining. A total of 36 strains (16 in seafoods, 17 in Korean pack-aged meals and 3 in other RTE foods) were identified as B. cereus by the analysis of 61 biochemical tests of the API 50CHB/20E system test and supplementary tests of $\beta$-hemolysis, rhizoid growth, motility and oxidase activity. The 28 strains out of 36 B. cereus isolates produced diarrhoeal enter-otoxin in Brain Heart Infusion (BHI) broth. All isolates were resistant to ampicillin and penicillin antibiotics, and most of them were susceptible to gentamicin, vancomycin, bacitracin, chloram-phenicol, kanamycin and streptomycin. The growth of B. cereus was affected by environmental temperature and incubation time. Culture with temperature under 1$0^{\circ}C$ effectively restricted the growth of B. cereus.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.446-451
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• 2015

The market for green vegetable juice (GVJ) is growing owing to the increasing demand for healthy food; however data on the safety and quality of GVJ are poorly reported. The objective of this study was to investigate the change in microbial community in GVJ during storage and its contamination by E. coli O157:H7. The microbial community was analyzed via culturable and non-culturable methods at 5, 10, and $25^{\circ}C$ for different storage times. In the non-culturable method, denaturing gradient gel electrophoresis (DGGE) was used. The initial bacterial concentration was $2.92{\times}10^5CFU/mL$, which exceeded the limit prescribed by the Korean Food Hygiene law. The results of the DGGE analysis indicated that the microbial community during storage was diverse and the spoilage lactic acid bacteria were prevalent at a later stage. Other bacteria such as Rahnella, Citrobacter, Pseudomonas, and Cyanobacteria were identified. Thus, the results strongly emphasize the need to pay attention to GVJ production safety, especially with respect to temperature control, in order to prevent the growth of foodborne pathogens such as E. coli O157:H7 and other spoilage bacteria.