국내에서 분리한 Cronobacter spp.(Enterobacter sakazakii)의 건조내성 특성

Tolerance of Korean Cronobacter spp. (Enterobacter sakazakii) Isolates to Dessication

  • 이은진 (경원대학교 식품생물공학과) ;
  • 류태화 (경원대학교 식품생물공학과) ;
  • 박종현 (경원대학교 식품생물공학과)
  • Lee, Eun-Jin (Department of Food Science and Biotechnology, Kyungwon University) ;
  • Ryu, Tae-Hwa (Department of Food Science and Biotechnology, Kyungwon University) ;
  • Park, Jong-Hyun (Department of Food Science and Biotechnology, Kyungwon University)
  • 발행 : 2009.12.31

초록

Cronobacter spp.(Enterbacter sakazakii)의 건조저항성은 다른 장내 세균들보다 강한 특성을 가지고 있는 것으로 알려져 있다. 본 연구는 국내 식품으로부터 분리한 110개의 Cronobacter균주로부터 건조내성 특성을 분석하고 여러 상대습도에서의 생존특성을 연구하고자 하였다. 국내 식품에서 분리한 Cronobacter 110균주중 8시간 금속표면 건조노출에 대하여 초기균수의 약 절반정도 생존하는 고내성그룹이 30%, 대부분이 사멸하는 저내성그룹이 약 10%를 차지하여 전체 균주 중 중간정도 이상의 내성을 가지는 균주가 90% 이상을 차지하고 있었다. 15일간 장기 건조노출에 경우도 비슷한 경향을 보여 주었다. 조제분유에서 Cronobacter 건조 노출의 경우 고내성그룹과 중간내성그룹은 30일 이후에도 5 log CFU/mL에서 3 log CFU/mL 이상의 생균수를 나타내었다. 오히려 금속 표면건조 때보다 더 생존율이 높아 조제분유에서는 더 내성이 증가함을 할 수가 있었다. 따라서 국내 식품에서 분리한 대부분의 Cronobacter도 건조에 강한 내성을 가지고 있는 것으로 보인다. 건조환경에서의 biofilm 형성능력은 고내성과 중간 내성그룹 균주는 노출초기에서부터 biofilm 생성이 이루어졌다. 그러나 저내성그룹 균주의 경우에는 biofilm의 형성이 증가하지 않다가 7일 후 biofilm 생성이 많아지는 것으로 분석되었다. 따라서 Cronobacter의 biofilm 형성능은 각 그룹간 biofilm 생성의 시간적인 차이만 존재하고 대부분의 Cronobacter는 건조스트레스에서 biofilm 형성능이 비슷한 것으로 보인다. Cronobacter는 건조금속표면의 75%의 상대습도에서 24-48시간 내에 모두 사멸하는 것으로 나타났으나 40% 상대습도에서는 초기균수의 60% 생균수를 유지하여 낮은 상대습도에 강한 저항특성을 보여주었다. 대부분의 Cronobacter는 건조에 강한 내성을 가지고 있어 조제분유등의 건조식품에서 오랫동안 살아 있을 수 있으나 습도가 높은 환경에서는 사멸이 많이 일어나는 것으로 사료된다. 그러므로 식품생산현장에서 습도를 조절하여 Cronobacter를 제어할 수 있을 것으로 보인다.

Cronobacter spp. (Enterobacter sakazakii) is known to be highly resistant to dry conditions than any other Enterobacteriaeae. In this study, one hundred and ten Korean Cronobacter isolates were characterized to find out their survival characteristics under conditions of desiccation and humidity. Thirty percentage strains of the isolates showed high resistance to desiccation exposed on the metal surface for eight hours by half survival of the initial number, whileas less than 10% strains showed dry sensitivity by less one log scale survival among seven log scales. Finally, more than 90% of the strains consisted of dry-resistant and dry-intermediate groups. The same tendencies were evident in a 15-day exposure. Dry-resistant and intermediate strain groups showed 3 log scale survival among 5 log initial numbers in the powdered infant formula for 30 days, which were more resistant than on the above metal surface exposed. So, almost the isolate strains showed high resistance to dry condition. Dry-resistant and intermediate groups exposed on the metal surface formed a biofilm at the beginning, and the dry-sensitive group showed biofilm formation mainly only after a 7-day exposure. However, without a time difference in formation of biofilm, the dry-resistant and sensitive isolates seemed to similar biofilm formation activity. Most of the isolates showed very low survival at 75% relative humidity in 48 hours; however, they showed high resistance by 60% survival at 40% relative humidity. The Cronobacter isolates showed high resistance to desiccation on the metal surface and in the powdered infant formula, but low survival at high relative humidity. Therefore, high humidity may be a control method for Cronobacter in food processing environments.

키워드

참고문헌

  1. Guillaume-Gentil O, Sonnard V, Kandhai MC. Marugg JD, Joosten H. A Simple and rapid cultural method for detection of Enterobacter sakazakii in environmental samples. J. Food Protect. 68: 64-69 (2005)
  2. Arad I, Baras M, Gofin R, Bar-Oz B, Peleg O. Dose parity affect the neonatal outcome of very-low-birth-weight inrants? Eur. J. Obstet. Gyn. R. B. 94: 283-289 (2001) https://doi.org/10.1016/S0301-2115(00)00308-0
  3. Farmer JJ, Asbury MA, Hickman FW, Brenner DJ. The Enterobacteriaceae study group. Enterobacter sakazakii: A new species of “Enterobacteriaceae” isolated from clinical specimens. Int. J. Syst. Bacteriol. 30: 369-58 (1980) https://doi.org/10.1099/00207713-30-3-569
  4. Jung MK, Park JH. Prevalence and thermal stability of Enterobacter sakazakii from unprocessed ready-to-eat agricultural products and powdered infant formulas. Food Sci. Biotechnol. 15: 152-155 (2006)
  5. Iversen C, Forsythe SJ. Risk profile of Enterobacter sakazakii, an emergent pathogen associated with infant milk formula. Food Sci. Technol. 14: 443-454 (2003) https://doi.org/10.1016/S0924-2244(03)00155-9
  6. Iversen C, Lehner A, Mullane N, Bidlas E, Cleenwerck I, Marugg J, Fanning S, Stephan R, Joosten H. The taxonomy of Enterobacter sakazakii: Proposal of a new genus Cronobacter gen. nov. and descriptions of Cronobacter sakazakii comb. nov., Cronobacter sakazakii subsp. sakazakii, comb. nov., Cronobacter sakazakii subsp. Malonaticus subsp. nov., Cronobacter turicensis sp. nov., Cronobacter muytjensii sp.nov., Cronobacter dublinensis sp. nov., and Cronobacter genomospecies 1. BMC Evol. Biol. 7: 64-67 (2007) https://doi.org/10.1186/1471-2148-7-64
  7. Gurtler JB, Kornacki JL, Beuchat LR. Enterobacter sakazakii: A colifrom of increased concern to infant health. Int. J. Food Microbiol. 104: 1-34 (2005) https://doi.org/10.1016/j.ijfoodmicro.2005.02.013
  8. Park JH, Jung MK. Food safety by Enterobacter sakazakii: Newly emergent pathogen from infant formula foods. Trends Agric. Life Sci. 3: 44-53 (2005)
  9. International Commission on Microbiological Specification for Foods (ICMSF). Microbiological Testing in Food Safety Management. Vol. 7. Academic/Plenum Publisher, New York, NY, USA (2002)
  10. Nazarowec-White M. Biological characterization of Enterobacter sakazakii. PhD thesis, University of Ottawa, Ottawa, Canada (1998)
  11. Breeuwer P, Lardeau A, PeterzM, Joosten HM. Desication and heat rolerande of Enterobacter sakazakii. J. Appl. Microbiol. 95: 967-973 (2003) https://doi.org/10.1046/j.1365-2672.2003.02067.x
  12. Barron JC, Forsythe SJ. Dry stress and survival time of Enterobacter sakakzakii and other Enterobacteriaceae in dehydrated powdered infant formula. J. Food Protect. 70: 2111-2117 (2007)
  13. Edelson-Mammel SG, Porteous MK, Buchanan RL. Survival of Enterobacter sakazakii in dehydrated powdered infant formula. J. Food Protect. 68: 1900-1902 (2005)
  14. Gurtler JB, Beuchat LR. Survival of Enterobacter sakazakii in powdered infant formula as affected by composition, water activity, and temperature. J. Food Protect. 70: 1579-1586 (2007)
  15. Lehner A, Stephan R. Microbiological, epidemiological, and food safety aspects of Enterobacter sakazakii J. Food Protect. 67: 2850-2857 (2004)
  16. O'Toole GA, Kaplan HB, Kolter R. Biofilm formation as microbial development. Annu. Rev. Microbiol. 54: 49-79 (2000) https://doi.org/10.1146/annurev.micro.54.1.49
  17. Lehner A, Riedel K, Eberl L, Breeuwer P, Diep B, Stephan R. Biofilm formation, extracellular polysaccharide production, and cell-to-cell signaling in various Enterobacter sakazakii strains: Aspect promoting environmental persistnace, J. Food Protect. 68: 2287-2294 (2005)
  18. Jung MK, Park JH. Prevalence and thermal stability of Enterobacter sakazakii from unprocessed ready-to-eat agricultural products and powdered infant formulas. Food Sci. Biotechnol. 15: 152-155 (2006)
  19. Kim SH, Park JH. Thermal resistance and inactivation of Enterobacter sakazakii Isolates during rehydration of powdered infant formula. J. Microbiol. Biotechnol. 17: 364-368 (2007)
  20. Nazarowec-White M, Farber JM. Thermal tolerance of Enterobacter sakazakii on reconstituted dried- infant formula. Lett. Appl. Microbiol. 24: 9-13 (1997) https://doi.org/10.1046/j.1472-765X.1997.00328.x
  21. Nazarowec-White M, McKeller RC, Piyasena P. Predicrive moneling of Enterobacter sakazakii inactivation in bovine milk during high-temperature shore-time pasterurization. Food. Res. Int. 32: 375-379 (1999) https://doi.org/10.1016/S0963-9969(99)00100-3
  22. Kim KP, Klumpp J, Loessner MJ. Enterobacter sakazakii bacteirophage can prevent bacterial growth in reconstituted infant formula. Int. J. Food Microbiol. 115: 195-203 (2007) https://doi.org/10.1016/j.ijfoodmicro.2006.10.029
  23. KFDA. Monitoring of Food-borne Pathogens on Ready-to-Eat Sunsik. Korea Food & Drug Administration, Seoul, Korea. pp. 15-21 (2006)
  24. Vasseur P, Vallet-Gely I, Soscia C, Genin S, Filloux A. The pel genes of the Pseudomonas aeruginosa PAK strain are involed at early and late stage of biofilm formation. Microbiology 151: 985-997 (2005) https://doi.org/10.1099/mic.0.27410-0
  25. InvitrogenTM LIVE/DEAD® BacLightTM Bacterial Viability Kits. Available from: http://probes.invitrogen.com/media/pis/mp07007. pdf. Accessed Oct. 23, 2006
  26. Gurtler JB, Kornacki JL, Beuchat LR. Enterobacter sakazakii: A colifrom of increased concern to infant health. Int. J. Food Microbiol. 104: 1-34 (2005) https://doi.org/10.1016/j.ijfoodmicro.2005.02.013
  27. Kumar, CG, Anand SK. Significance of microbial biofilms in food industry: A review. Int. J. Food Microbiol. 42: 9-27 (1998) https://doi.org/10.1016/S0168-1605(98)00060-9
  28. Ryu, JH, Kim H, Beuchat LR. Attachment and biofilm formation by Escherichia coli O157:H7 on stainless steel as influenced by exopolysaccharide production, nutrient availability, and temperature. J. Food Protect. 67: 2123-2131 (2004)
  29. Iversen C, Lane M, Forsythe SJ. The growth profile, thermotolerance, and biofilm formation of Enterobacter sakazakii grown in infant formula milk. Lett. Appl. Microbiol. 38: 378-382 (2004) https://doi.org/10.1111/j.1472-765X.2004.01507
  30. Frank JF, Ehlers J, Wicker L. Removal of Listeria monocytogenes and poultry soil-containing biofilms using chemical cleaning and sanitizing agents under static conditions. Food Prot. Trends 23: 654-663 (2003)
  31. Norwood DE, Gilmour A. The growth and resistance to sodium hypochlorite of Listeria monocytogenes in a steady-state multispecies biofilm. J. Appl. Microbiol. 88: 512-520 (2000) https://doi.org/10.1046/j.1365-2672.2000.00990.x
  32. Mullane NR, Whyte P, Wall PG, Quinn T, Fanning S. Application of pulsed-field gel electrophoresis to characterize and trace the prevalence of Enterobacter sakazakii in an infant formula processing facility. Int. J. Food Microbiol. 116: 73-81 (2007) https://doi.org/10.1016/j.ijfoodmicro.2006.12.036