• Title/Summary/Keyword: microbiological analysis

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Comparison of Digital PCR and Quantitative PCR with Various SARS-CoV-2 Primer-Probe Sets

  • Park, Changwoo;Lee, Jina;Hassan, Zohaib ul;Ku, Keun Bon;Kim, Seong-Jun;Kim, Hong Gi;Park, Edmond Changkyun;Park, Gun-Soo;Park, Daeui;Baek, Seung-Hwa;Park, Dongju;Lee, Jihye;Jeon, Sangeun;Kim, Seungtaek;Lee, Chang-Seop;Yoo, Hee Min;Kim, Seil
    • Journal of Microbiology and Biotechnology
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    • v.31 no.3
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    • pp.358-367
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    • 2021

  • The World Health Organization (WHO) has declared the coronavirus disease 2019 (COVID-19) as an international health emergency. Current diagnostic tests are based on the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) method, which is the gold standard test that involves the amplification of viral RNA. However, the RT-qPCR assay has limitations in terms of sensitivity and quantification. In this study, we tested both qPCR and droplet digital PCR (ddPCR) to detect low amounts of viral RNA. The cycle threshold (CT) of the viral RNA by RT-PCR significantly varied according to the sequences of the primer and probe sets with in vitro transcript (IVT) RNA or viral RNA as templates, whereas the copy number of the viral RNA by ddPCR was effectively quantified with IVT RNA, cultured viral RNA, and RNA from clinical samples. Furthermore, the clinical samples were assayed via both methods, and the sensitivity of the ddPCR was determined to be equal to or more than that of the RT-qPCR. However, the ddPCR assay is more suitable for determining the copy number of reference materials. These findings suggest that the qPCR assay with the ddPCR defined reference materials could be used as a highly sensitive and compatible diagnostic method for viral RNA detection.

  • https://doi.org/10.4014/jmb.2009.09006 인용 PDF KSCI

A Study on Microbiological Hazard Analysis according to the Steaming Process of Various Rice Cakes

  • Kim, Jung-Yun;Park, Da-Hyun;Rha, Young-Ah
    • Culinary science and hospitality research
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    • v.23 no.6
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    • pp.20-26
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    • 2017

  • To guarantee the safety of rice cake production, the Hazard Analysis Critical Control Points system was applied to the production process. The purpose of this study was to analyze the microbiological hazards of the manufacture of rice cakes, and establish critical limits in the process of the manufacturing rice cakes. To control the microbiological hazards, the sterilization process was set to a critical limit. The process of manufacturing rice cakes can reduce these microbiological hazards during the steaming process. A microorganism test for each specimen was conducted three times and compared with before and after steaming processes. The finished product was conducted by microbiology experiment and the validity of the steaming process was verified. The results were determined to be capable of reducing the biological element of Critical Control Point via the steaming process. Microbiology such as aerobic plate count, coliform, Escherichia coli(E. coli), Listeria monocytogenes, Enterohemorrhagic E. coli, Salmonella spp., Bacillus cereus, Staphylococcus aureus and Clostridium perfringens was evaluated by the experimental method of Korean Food Standards Codex. Aerobic plate count was reduced by steaming process, and no microorganism were detected. All rice cakes in the finished product were judged to be safe for both the Escherichia coli and general bacteria. In conclusion, it suggested that a HACCP plan was necessary for management standard and systematic approach in the establishment of critical limit, problem resolution, verification method, education, and records management. Based on this study, it is intended to provide a baseline for improving quality control standards and improving hygiene levels for small manufacturers.

  • https://doi.org/10.20878/cshr.2017.23.6.003 인용 PDF KSCI

Hazard Analysis of Commissary School Foodservice Operations (공동조리 학교급식의 미생물적 품질보증을 위한 위험요인 분석)

  • 곽동경;남순란;김정리;박신정;서소영;김성희;최은희
    • Korean journal of food and cookery science
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    • v.11 no.3
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    • pp.249-260
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    • 1995

  • 6 Central commissary and 2 conventional school foodservice operations were assessed in terms of time-temperature relationship and microbiological quality, and monitoring control methods were identified through hazard analysis during the phases of prodution and distribution. 2 conventional schools from Seoul and 6 commissary schools from Kyungkido were participated in the survey. Meals produced in central commissary were distributed to satellites, therefore delivery practices of foods were identified as critical. Microbiological test results for commissary and conventional schools revealed that microbiological quality of foods was mainly related to time-temperature management, types of food, and equipment sanitation not to the foodservice system used. Time-temperature profiles at temperature danger zone (7.2-60$^{\circ}C$) observed were to be related to the following sanitary practices: cooked vegetables were held at temperature danger zone for relatively longer delayed time (15-38$^{\circ}C$: 15-226 min, 7-60$^{\circ}C$: 75-226 min), and same results were observed for deep-fat fried cutlets (15-38$^{\circ}C$: 15-151 min, 7-60$^{\circ}C$: 33-151 min). Menu items with various ingredients and frequent contacts with hands and equipments during the production flow were held at temperature danger zone for longer delaying time than other menu items with brief prodution stages. Based on hazard analysis critical control points, microbiological quality was collectively affected by time-temperature relationships, equipment sanitation, proper cooking methods, and sanitary management competencies of dietitians. Microbiological test results of working equipments and surface of dishes and trays showed that immediate action should be taken. Cutting boards used in central kitchen were also showed similar results of potential dager of cross-contamination. Effective sanitary control methods were urgently needed.

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