• Journal of Food Hygiene and Safety
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• v.37 no.2
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• pp.80-86
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• 2022

The purpose of this study was to examine the microbiological and physicochemical changes on packaged tofu stored at temperatures of 5, 13, 23, and 30℃, and measure the consumable period from the expiry date to ultimately evaluate the microbiological safety on the extension of the consumable period. From the investigation, the pH value of tofu at each storage temperature (5, 13, and 23℃) showed a slight decrease over the storage period, although there was no significant change. The hardness of packaged tofu decreased more rapidly as temperature and storage time increased and the tofu started to show signs of decomposition at the same time. Analysis on the microbial change of tofu at different storage temperature revealed that the number of general bacteria also increased as the temperature increased. It was further found that packaged tofu takes 25 days at 5℃, 7 days at 13℃, and 1 day at 23℃ from the expiry date until the general bacteria count is at least at the early decomposition level which is 10℃ log CFU/g. However, no coliform bacteria was detected from tofu after storing at 5, 13 and 23℃. When packaged tofu was stored at 5℃, the L value changed significantly after 26 days, whereas the a and b values showed no significant change during the storage period (P>0.05). When storing tofu at 13℃ and 23℃ the L value decreased after 8 and 3 days, respectively. However, both a and b values increased (P<0.05).

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1996.06a
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• pp.33-33
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• 1996

Interests in the field of rapid methods and automation in microbiology have been growing steadily on an international scale in recent years. International meetings concerned this problem have been held in elsewhere in the world countries since the past twenty years. But, unfortunately in the field of microbial examination in food hygiene, this problem have not yet been developed so much as in the field of clinical microbiology. Today, I would like to introduce you here present aspects of rapid and automation technologies, those which are manly carrying in milk and meats industries. My illustration will be given recent improved technologies using automatic apparatus and instruments along with process of microbial count procedure. Recent direct microbiological counting system (ChemeScan \ulcorner) as real time ultrasensitive analysis created by Cheminex Ltd., France is now most evolutional instrument to provide direct microbial counts, down to one cell, within 30 minutes. The results from these evaluations how a good correlation between the ChemScan system and the standard plate count method. This system will be successful application for not only in the field of pharmacology but also food microbiology. In addition, current identification of microbes by sophisticated instruments suitable for food microbiology, one of which Biology is manual system (BIOLOG\ulcorner), provides reference-level capability at a modes price. For the manual system, the color reactions in the microplate are read by eye and manually keyed into personal computer. Species identification appears on the computer screen within seconds, along with biotype patterns, a list of closely related species, and other useful statistics. In present this is useful application for microbial ecology and epidemiological survey. RiboPrinter system newly produced by DuPont is now focusing among microbiologists in the world, and is one of the biggest microbial characterization system using a DNA-based approach. The technology analyzer is bacterial culture for its genetic fingerprint or riboprint pattern. Finally Bio-cellTracer system for automatic measurement of fungal growth and Fukitori-Maseter, a Surface Hygiene Monitoring Kit by using swabe procedure in food processing environment are briefly illustrated in this presentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1072-1078
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• 2015

To maintain high quality and microbiological safety of paprika during storage for export, paprika samples after harvest were treated with 75 ppmv chlorine dioxide ($ClO_2$) gas and stored at $8^{\circ}C$, which is the optimal storage temperature, for 30 days. $ClO_2$ gas treatment reduced initial populations of total aerobic bacteria in samples by 1.62 log CFU/g as well as yeast and molds by 1.45 log CFU/g compared to those of the control. During storage, weight loss of all samples increased, and samples treated with $ClO_2$ gas showed lower weight loss than the control. In addition, total soluble solid and total phenolic contents were not significantly different between the samples during storage, whereas vitamin C content and hardness of all samples decreased. Hunter L, a, and b values of paprika samples were not significantly different between the treatments. These results suggest that $ClO_2$ gas treatment can be effective for improving microbiological safety and maintaining high quality of paprika during storage.

• Journal of the FoodService Safety
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• v.5 no.1
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• pp.19-29
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• 2024

Medicinal cooked rice with Astragalus membranaceus extract and garlic was developed as a ready-to-eat product. The response surface methodology was used to examine the effect of garlic and Astragalus membranaceus extract addition on the color, texture, and sensory properties to optimize the product. The product was also analyzed for microbiological, sensory, and physical property changes during storage.As for the color, taste, and overall acceptability, the sensory scores increased with the increase of Astragalus membranaceus extracts (p<0.05). The sensory scores for the product ranged between 9.17~9.92 and foodborne microorganism such as Bacillus cereus, Salmonella, Staphylococcu aureus, and Eschericha coli were not detected after 13 storage days. Therefore, the possible shelf life was evaluated for up to13 days of storage. When considering health and convenience are important factors in the development of new food products, the medicinal and biological effects of garlic and Astragalus membranaceus could be useful for providing healthy diet options for senior consumers. The results of sensory and microbiological tests showed the potential for the commercialization of ready-to-eat cook-chill product as an alternative of cooked rice for Asian populations and Korean senior consumer market.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.146-151
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• 2020

This study investigated microbiological safety of employees' hands, dining tables, and indoor air in cooking areas and lunchrooms in child care centers. Microbiological tests were performed according to the Korea Food Code. Total numbers of aerobic bacteria and coliform bacteria were measured as 5.8±1.9 log CFU/hand and 4.0±2.4 log CFU/hand on employees' hands, and 4.3±3.0 log CFU/100 ㎠ and 2.6±3.3 log CFU/100 ㎠ on dining tables. Bacillus cereus were detected in two cases each of employees' hands and dining tables, respectively. The analysis of microbiological contamination of indoor air in chid care centers showed that the total numbers of aerobic bacteria and coliform bacterial were 28±7.2 CFU/plate and 3.1±2.9 CFU/plate, respectively. Bacillus cereus and Staphylococcus aureus were counted as 1.7±0.2 CFU/plate and 1.6±0.5 CFU/plate from the indoor air in child cate centers. These results indicate that indoor-air in child care centers is considered more safe compared to previous reports. In conclusion, it is necessary to carry out hygienic management using alcohol-based disinfectants before meals to remove microorganism contamination on dining tables and hands. In order to reduce microbial contamination in indoor air, it is also deemed necessary to freshen the sanitary caps, masks, and clothing of the catering staff with periodic ventilation of indoor air.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.367-373
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• 2019

In order to evaluate the microbiological safety of ice cream products, the total viable bacterial counts were measured in 6 kinds of ice pops, 5 kinds of non-milk fat ice cream, and 5 kinds of milk fat ice cream, sold in local markets. In addition, E. coli, S. aureus, B. cereus, and L. monocytogenes were artificially inoculated in three types of ice cream products and stored at $-5^{\circ}C$, $-10^{\circ}C$, and $-18^{\circ}C$, respectively, and after inoculation, viable cells were measured periodically. As a result of the total viable count, about 1~2 log CFU/mL was detected in 16 kinds of ice cream products. As a result of inoculation with microorganisms at various temperatures, the number of viable cells decreased as the storage period became longer, and the higher the storage temperature, the faster the microorganisms died. Especially, the microorganisms were killed faster in the ice pop products than in the other ice cream products, and the microorganisms were killed relatively slower in the milk ice cream. L. monocytogenes and S. aureus were relatively stable in frozen conditions compared to other microorganisms. The microbial contamination of commercial ice cream was lower than the allowable standard of the Korean Food Code. Microorganisms did not proliferate when the microorganism was inoculated at freezing temperature. Therefore, it is expected that the microbiological safety of frozen foods will be ensured if the sanitary control and disinfection of raw materials are thoroughly carried out during the production of frozen confections and the temperature control during distribution and storage is well maintained.

• Korean journal of food and cookery science
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• v.2 no.2
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• pp.21-31
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• 1986

Here is a research on hospital foodservice system, when korea traditional food of pyeon yuk and bin dae deok were used by ready-prepared foodservice system, it was estimated the preservations of microbiological quality and sensory quality. All data collection was replicated three times. The results were as following; 1. In time and temperature data, two menu items were needed internal temperature below $7^{\circ}C$ in a cooling stage, and in the case of cook/chill storage, the days were shortened within weeks, and the holding time must be possiblely minimized. Finally foods were served sanitary. 2. In view of microbiological safety, in the case of cook/chill storage as $0{\sim}4^{\circ}C$ the days must be shortened within 2 weeks and its was possible to store until 6 weeks in $-20{\sim}-23.3^{\circ}C$. So to preserve pre-cooked food longly, it was effective to freeze them quickly by using vacuum package and to reheat them by a microwave oven before serving and to serve lastly in microbiological quality. 3. Hospital ready-prepared foodservice system with food storage in plastic bags, biochemical test of C. Perfingens C. botulinum and Salmonella were not detected. 4. By using of a microwave oven, it had effects of thawing, reheating and sterilizing of chilled and frozen foods in a short time. 5. Sensory evaluations were made by a 10-member panel using five scoring tests. Because sensory of quality was lowered in the case of chilled storage, it was possible to serve foods within 2 weeks. Texture and aroma were preserved by cook/frozen system and usually there was no significance from 4 weeks until 6 weeks, but considering of the objects, it was good to store until 4 weeks in sensory quality.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.809-814
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• 2021

This study was performed to evaluate the microbiological quality of fresh cut fruits in Korea. Forty freshly cut fruit samples were assessed for aerobic mesophilic count (AM), aerobic psychrophilic count (AP), total coliform, generic Escherichia coli, yeast and mold (YM), Bacillus cereus, Staphylococcus aureus, Salmonella spp., and E. coli O157:H7. The average value for AM, AP, and YM was 4.51, 5.35, and 4.31 log CFU/g, respectively. The average of the total coliform was 2.42 log CFU/g, and E. coli was not detected in all samples. For foodborne pathogen bacteria, B. cereus and S. aureus were detected in 2.5 and 7.5% samples, respectively, and Salmonella spp. and E. coli O157:H7 were not detected in all samples. Among the samples, pear generally had the highest contamination level. Therefore, to assure the safety of fresh cut fruits, low temperature and thorough hygiene management should be implemented.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.841-846
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• 2013

Developing a menu for foodservice operations utilizing a Yaksun meets with the desire of customers who have keen interest in health food. In addition, it is possible to expect the additional advantage of decreasing hygiene risk, which can be caused by large quantity cooking, by the efficacy of medicinal herbs used in Yaksun. Accordingly, this study provides with basic information for the development of a Yaksun menu for foodservice operations utilizing Gwackhyang by evaluating the sensory quality and microbiological quality of bean soup added of Gwackhyang. The standard plate counting significantly decreased as the addition quantity of Gwackhyang increased (p<0.001). All bean soups, which were kept at room temperature and refrigerator for 3 hours after cooking, met the safety standard 5.00 CFU/g. The number of coliforms also significantly decreased as the addition quantity of Gwackhyang increased. The bean soups in control group exceeded the safety standard of 2.00 CFU/g after 1 hour at room temperature and in refrigerator. On the other hand, all Gwackhyang bean soups met safety standard, only excluding G1 with 1% Gwackhyang kept at room temperature. Accordingly, it has been confirmed that the addition of Gwackhyang during bean soup production decreases the microorganism level of bean soup. Both standard plate counting and the number of coliforms significantly increased after 3 days in refrigerator; however, the increasing extent of Gwackhyang bean soups were less than the control group bean soups. The control group received scored highest in 3 sensory characteristics out of 5 sensory characteristics. However, G1 with 1% Gwackhyang also scored highest in 2 sensory characteristics, which were taste and overall preference. G2 also scored 4.45 in color and 4.15 in fragrance, which were lower than the control group but were above average.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.845-852
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• 2014

The quality of commercial sauce products was evaluated through pH, soluble solid content, salinity, water activity and microbial analyses. The pH of sauces was 2.38~5.30, soluble solids were between 6.03 and 71.67, and distributions of salt were 0.23~5.00% in 32 commercial sauce products. In addition, water activity of vinegar red pepper sauce and spicy soft tofu stew stock were determined 0.773 and 0.988, respectively. Yeast, mold, Staphylococcus aureus, E. coli and coliform were not detected in any sauces. Higher level of total viable cells (TVC) resulted in pH over 4.2. TVC of shelf-stable sauces was 1.0~3.6 log CFU/g. TVC of seven sauce products was classified as non-potentially hazardous foods by temperature controlled for safety standard (TCS), even though levels were over acceptable guidelines of the USDA (3 log CFU/g). These results indicate that the standard and classification of commercial sauce products should be modified and controlled strictly.