Monitoring microbiological contamination, pre-decontamination, and irradiation status of commercial dried laver (Porphyra sp.) products

시판 유통 김의 미생물 오염도, 사전 살균처리 및 전자선 조사 여부 확인

  • Lee, Eun-Jin (School of Food Science & Biotechnology, and Food Bio-industry Research Institute, Kyungpook National University) ;
  • Kim, Gui-Ran (School of Food Science & Biotechnology, and Food Bio-industry Research Institute, Kyungpook National University) ;
  • Lee, Hye-Jin (School of Food Science & Biotechnology, and Food Bio-industry Research Institute, Kyungpook National University) ;
  • Kwon, Joong-Ho (School of Food Science & Biotechnology, and Food Bio-industry Research Institute, Kyungpook National University)
  • 이은진 (경북대학교 식품공학부.식품생물산업연구소) ;
  • 김귀란 (경북대학교 식품공학부.식품생물산업연구소) ;
  • 이혜진 (경북대학교 식품공학부.식품생물산업연구소) ;
  • 권중호 (경북대학교 식품공학부.식품생물산업연구소)
  • Received : 2016.07.28
  • Accepted : 2016.10.08
  • Published : 2017.02.28


Eighteen commercial laver (Porphyra sp.) products were purchased from Korean market and were monitored for their microbial contamination, pre-decontamination, and luminescence properties. The laver samples showed considerable variation in their microbial contamination, from $10-10^7CFU/g$ of total aerobic counts, <$10-10^2CFU/g$ of coliforms in 4 dried laver samples, and <$10-10^6CFU/g$ of yeasts and molds except in 3 samples. In addition, $10^2CFU/g$ of Bacillus cereus was found in one sample. DEFT/APC analysis was suitable for demonstrating whether the samples were pre-decontaminated or not, with DEFT/APC values lower than 2.0 log for non-heated samples and 1.0-8.5 log for heatprocessed samples. In photostimulated luminescence (PSL) calibration, 15 samples irradiated at 1 kGy showed positive (irradiated) values more than 5000 PCs. Furthermore, thermoluminescence (TL) analysis by separating the marker minerals from samples revealed the potential to be employed in identifying irradiation status by determining $1^{st}$ TL glow at $125-175^{\circ}C$ and TL ratio ($TL_1/TL_2$) of all the samples.


dried laver;microbial contamination;irradiation;DEFT/APC;PSL/TL


Supported by : 한국연구재단


  1. Hwang MS, Kim SM, Ha DS, Baek JM, Kim HS, Choi HG. DNA sequences and identification of Porphyra cultivated by natural seeding on the southwest coast of Korea. Algae 20: 183-196 (2005)
  2. Kang KH, Choi SK, Ko AK, Kim HL, Kim KM, Park SI. Production of the cause of bacterial contamination in Kimbab and its ingredient. J. Food Hyg. Safety. 10: 175-180 (1995)
  3. Lee HJ, Byun HS, Kim JH, Park HY, Jung KJ, Lee TS. Bacterial contamination of dried laver products. Bull. Nat. Fish. Res. Devel. Ins. 57: 221-226 (1999)
  4. Lee TS, Lee HJ, Byun HS, Kim JH, Park MJ, Park HY, Jung KJ. Effect of heat treatment in dried lavers and modified processing. J. Korean Fish. Soc. 33: 529-532 (2000)
  5. Jo CR, Lee NY, Hoog SP, Kim YH, Byun MW. Microbial contamination of food materials for manufacturing korean laver roll (Kimbab) and the effect of gamma irradiation. J. Food Sci. Nur. 9: 236-239 (2004)
  6. Chung HJ, Lee NY, Jo CR, Shin DH, Byun MW. Use of gamma irradiation for inactivation of pathogens inoculated into Kimbab, steamed rice rolled by dried laver. Food Control. 18: 108-112 (2007)
  7. Kim BR, Kim AJ, Shin JK. Effect of sterilization by intense pulsed light on radiation-resistant bacterium, Micrococcus roseus. Korean J. Food Sci. Technol. 45: 248-251 (2013)
  8. FAO/WHO CODEX STAN. General Codex Methods For The Detection of Irradiated Foods. CODEX STAN 231-2001, Rev.1. Rome, Italy. p. 1 (2003)
  9. Lee NY, Jo C, Chung HJ, Kang HJ, Kim JK, Kim HJ, Byun MW. The prediction of the origin of microbial contamination in Kimbab and improvement of microbiological safety by gamma irradiation. Korean J. Food Sci. Technol. 37: 279-286 (2005)
  10. MFDS. Food Code. Ministry of Food and Drug Safety. Cheongwon, Korea. pp. 2-8 (2014)
  11. Shin YP, Choi JW, Yeon JH, Lee MJ, Oh DH, Hong CH, Bahk GJ, Woo GJ, Park JS, Ha SD. Assessment of contamination level of foodborne pathogens in the main ingredients of Kimbab during the preparing process. Korean J. Food Sci. Technol. 37: 122-128 (2005)
  12. Anderson A, Ronner U, Granum PE. What problemes does the food industry have with the spore-forming pathogenes. Bacillus cereus and Clostridium perfrigenes. Int. J. Food Microbial. 28: 145-155 (1995)
  13. Waje CK, Jun SY, Lee YK, Kim BN, Han DH, Jo C, Kwon JH. Microbial quality assessment and pathogen inactivation by electron beam and gamma irradiation of commercial seed sprouts. Food Control. 20: 200-204 (2009)
  14. Kim BH, Kim HJ, Yoon Y, Shin MG, Lee JW. Comparison of the effects of gamma ray and electron beam irradiation to improve safety of spices for meat processing. Korean J. Food Sci. Ani. Resour. 30: 124-132 (2010)
  15. Wirtanen G, Sjoberg AM, Boisen F, Alanko T. Microbiological screening method for indication of irradiation of spices and herbs: A BCR collaborative Study. J. AOAC Int. 76: 674-681 (1993)
  16. Oh KN, Lee SY, Yang JS. Detection of gamma-irradiated grains by using DEFT/APC method. Korean J. Food Sci. Technol. 34: 380-384 (2002)
  17. Choi JI, Kim HJ, Ahn DH, Chun BS, Lee JW. Application of gamma ray irradiation to the microbiological safety of dried seafood products. Kor. J. Fish Aquat. Sci. 43: 169-173 (2010)
  18. Jeong MS, Ahn JJ, Akram K, Kim GR, Kim HK, Kwon JH. Monitoring of commercial red pepper powders for their irradiation status. Korean J. Food Sci. Technol. 44: 673-679 (2012)
  19. Pinnioja S, Pajo L. Thermoluminescence of minerals useful for identification of irradiated seafood. Radiat. Phys. Chem. 46: 753-756 (1995)
  20. Ahn JJ, Akram K, Jeong MS, Kwak JY, Jang YD, Kwon JH. Radiation-induced thermoluminescence characteristics of feldspar following different heat and microwave treatments. J. Lumin. 132: 1964-1968 (2012)
  21. Yun H, Kim HJ, Jung YJ, Jung S, Lee JW, Jo C. Effect of natural ingredients and red wine for manufacturing meat products on radiation sensitivity of pathogens inoculated into ground beef. Korean J. Food Sci. Ani. Resour. 30: 819-825 (2010)
  22. CEN. Detection of irradiated food using Direct Epifluorescent Filter Technique/Aerobic Plate Count (DEFT/APC)-Screening method. Committee European Normalization, Brussels, Belgium. English version of EN 13783 (2000)
  23. Wirtanen G, Sjoberg AM. A microbiological method (DEFT/APC) for the identification of irradiated spices and seafood. pp. 25-34. In: Workshop on Recent Advances on Detection of Irradiated Food. Leonardi M, Raffi JJ, Belliardo JJ (eds). Commission of the European Communities. Luxembourg, Luxembourg (1993)
  24. EN13751. Foodstuffs-Detection of irradiated food using photostimulated luminescence. European Committee for Standardization (CEN), Brussels, Belgium (2009)
  25. EN1788. Foodstuffs-thermoluminescence detection of irradiated food from which silicate minerals can be isolated. European Committee for Standardization (CEN), Brussel, Belgium (2001)
  26. MFDS. Food Code. Ministry of Food and Drug Safety. Cheongwon, Korea. pp. 9-47 (2014)
  27. MFDS. Food Code. Ministry of Food and Drug Safety. Cheongwon, Korea. pp. 9-46 (2014)