Growth Potential of Escherichia coli O157:H7 in Lettuce Leaf Extract and on Lettuce Leaf Surface

상추잎 즙액과 표면에서 Escherichia coli O157:H7의 생장 가능성

  • Kim, Won-Il (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Jung, Hyang-Mi (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Kim, Se-Ri (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Park, Kyeong-Hun (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Kim, Byung-Seok (Administrative management & Legal affairs office, RDA) ;
  • Yun, Hye-Jung (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Yun, Jong-Chul (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA) ;
  • Ryu, Kyoung-Yul (Microbial Safety Division, Agri-Food Safety Department, National Academy of Agricultural Science, RDA)
  • 김원일 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 정향미 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 김세리 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 박경훈 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 김병석 (농촌진흥청 행정법무담당관실) ;
  • 윤혜정 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 윤종철 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과) ;
  • 류경열 (농촌진흥청 국립농업과학원 농산물안전성부 유해생물과)
  • Received : 2011.08.03
  • Accepted : 2011.10.10
  • Published : 2011.12.31

Abstract

This study was to evaluate the growth potential of E. coli O157:H7 in lettuce leaf extracts and on lettuce leaf surface at various temperatures. The pathogen can survive and multiply in the extracts and leaf surface of lettuce. The population of E. coli O157:H7 in the lettuce extracts reached to 4.79 log CFU/mL at $37^{\circ}C$. The multiplication of pathogen in lettuce extracts initiated within 10 hours of inoculation over $15^{\circ}C$ conditions. And it can survive in the lettuce leaf extracts at $4^{\circ}C$ for 100 hours at least. And this pathogen can multiply on lettuce leaf surface and the population of pathogen on the lettuce leaf surface increased to 1.82 log CFU/g at $25^{\circ}C$. At $37^{\circ}C$, the pathogen density increased to 1.53 CFU/g within 3 days after inoculation. At all temperature, irrespective of the inoculation level, similar trends in growth of E. coli O157:H7 were observed. These results emphasize the growth potential of E. coli O157:H7 in lettuce leaf extract and on lettuce leaf surface. To reduce the risk of outbreak, it is important to maintain the cold chain system during storage before the consumption.

본 연구에서는 식중독을 일으키는 병원균인 Escherichia coli O157:H7이 주요 소비 엽채류인 상추에서의 생장 가능성과 온도대별 생장변화를 구명하기 위하여 상추잎 즙액 에서 E. coli O157:H7의 생장, 상추잎 표면에서의 생장, 여러 가지 온도조건하의 상추잎 즙액 및 표면에서 E. coli O157:H7의 생장, 초기 접종 농도별 생장패턴을 조사하였다. E. coli O157:H7은 상추잎 즙액에서 20시간 이내에 밀도가 증가하였고 상추잎 즙액의 농도에 따라 병원균의 생장률은 다르게 나타났다. 조사기간 동안 $4^{\circ}C$ 조건에서는 E. coli Ol57:H7 밀도가 크게 변하지 않았고 $15^{\circ}C$ 이상의 조건에서는 10시간 이내에 밀도가 증가승하는 것을 확인할 수 있었다. 상추잎 표면에서도 E. coli Ol57:H7의 밀도는 초기 접종 밀도에 비해 증가하였고, 증가되는 정도는 온도가 높아질수록 증가율이 높은 것으로 나타났다. 상추의 E coli O157:H7 초기 오염 농도가 병원균의 최대 생장 밀도 에 큰 영향을 미치는 것으로 확인되었다. 따라서 본 연구 결과로부터 상추잎에서 식중독세균인 E. coli O157:H7의 생장이 일어나는 것을 확인하였고, 이는 온도의 영향을 많이 받는 것으로 나타났다. 위의 결과에 따라 농식품 안전성 확보를 위해서는 신선 엽채류는 생산 유통 소비 단계 에서 유해미생물의 오염을 예방하는 것이 중요하고 특히 유통과 소비단계에서 저온도 유지가 철저히 이루어져야 할 것으로 사료된다.

Keywords

Acknowledgement

Supported by : 농업진흥청, 국립농업과학원

References

  1. 통계청: 농작물생산조사, (2010).
  2. 식품의약품안전청: 식품의약품안전청 용역연구개발과제 최종보고서, (2009).
  3. Abdul-Raouf, U. M., Beuchat, L. R. and Ammar, M. S.: Survival and growth of Escherichia coli O157:H7 on salad vegetables. Appl. Environ. Microbiol., 59, 1999-2006 (1993).
  4. Alegre, I., Abadias, M., Anguera, M., Oliveira, M. and Vinas, I.: Factors affecting growth of foodborne pathogens on minimally processed apples. Fd Microbiol, 27, 70-76 (2010). https://doi.org/10.1016/j.fm.2009.08.005
  5. Brandl, M. T.: Plant lesions promote the rapid multiplication of Escherichia coli O157:H7 on postharvest lettuce. Appl. Environ. Microbiol., 74, 5285-5289 (2008). https://doi.org/10.1128/AEM.01073-08
  6. Brandl, M. T. and Amundson, R.: Leaf age as a risk factor in contamination of lettuce with Escherichia coli O157:H7 and Salmonella enterica. Appl. Environ. Microbiol., 74, 2298-2306 (2008). https://doi.org/10.1128/AEM.02459-07
  7. Choi, J. W., Park, S. Y., Yeon, J. H., Lee, M. J., Chung, D. H., Lee, K. H., Kim, M. G., Lee, D. H., Kim, K. S. and Ha, S. D.: Microbial contamination levels of fresh vegetables distributed in markets. J. Fd hyg. Safety., 20, 43-47 (2005).
  8. Harapas, D., Premier, R., Tomkins, B., Franz, P. and Ajlouni, S.: Persistence of Escherichia coli on injured vegetable plants. J. Food Microbiol., 138, 232-237 (2010). https://doi.org/10.1016/j.ijfoodmicro.2010.01.022
  9. Janisiewicz, W. J., Brown, M. W., Sapers, G. M., Fratamico, P. and Buchanan, R. L.: Fate of Escherichia coli O157:H7 on fresh-cut apple tissue and its potential for transmission by fruit flies. Appl. Environ. Microbiol., 65, 1-5 (1999).
  10. Jennifer, L. K., Craig, T. P., Danielle, G. and Brandl, M. T.: Transcriptome analysis of Escherichia coli O157:H7 exposed to lysates of lettuce leaves. Appl. Environ. Microbiol., 76, 1375-1387 (2010). https://doi.org/10.1128/AEM.02461-09
  11. Jiang, X., Morgan, J. and Doyle, M. P.: Fate of Escherichia coli O157:H7 in manure-amended soil. Appl. Environ. Microbiol., 68, 2605-2609 (2002). https://doi.org/10.1128/AEM.68.5.2605-2609.2002
  12. Lang M. M., Harris, L. J. and Beuchat, L. R.: Survival and recovery of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on lettuce and parsley as affected by method of inoculation, time between inoculation and analysis, and treatment with chlorinated water. J. Food Prot., 67, 1092- 1103 (2004).
  13. Mandrell, R. E.: Enteric human pathogens associated with fresh produce: sources, transport and ecology. IFT/Blackwell Publishing, Ames, IA., p. 3-42 (2009).
  14. Oliveira, M., Usall, J., Solsona, C., Alegre, I., Vinas, I. and Abadias, M.: Effects of packaging type and storage temperature on the growth of foodborne pathogens on shredded 'Romaine' lettuce. Food Microbiol., 27, 375-380 (2010). https://doi.org/10.1016/j.fm.2009.11.014
  15. Marek, P., Nair, M. K. M., Hoagland, T. and Venkitanarayanan, K.: Survival and growth characteristics of Escherichia coli O157:H7 in pasteurized and unpasteurized Cheddar cheese whey. J. Food Microbiol., 94, 1-7 (2004). https://doi.org/10.1016/S0168-1605(03)00331-3
  16. Samara, A. and Koutsoumanis, K. P.: Effect of treating lettuce surfaces with acidulants on the behavior of Listeria monocytogenes during storage at 5 and 20oC and subsequent exposure to simulated gastric fluid. Int. J. Food Microbiol., 129, 1-7 (2009). https://doi.org/10.1016/j.ijfoodmicro.2008.10.023
  17. Strawn, L. K. and Danyluk, M. D.: Fate of Escherichia coli O157:H7 and Salmonella spp. on fresh and frozen cut mangoes and papayas. Food Microbiol., 138, 78-84 (2010). https://doi.org/10.1016/j.ijfoodmicro.2009.12.002
  18. Vinten, A. J. A., Lewis, D. R., Fenlon, D. R., Leach, K. A., Howard, R., Svoboda, I. and Ogden, I.: Fate of Escherichia coli and Escherichia coli O157 in soil and drainage water following cattle slurry application at 3 sites in southern Scotland. Soil Use and Management, 18, 223-231 (2002).
  19. Wachtel, M. R., Whitehand, L. C. and Mandrell, R. E.: Association of Escherichia coli O157:H7 with preharvest leaf lettuce upon exposure to contaminated irrigation water. J. Food prot., 65, 18-25 (2002).
  20. 세계무역기구(Http://www.wto.org). (1995).
  21. 미국 질병통제예방 센터(Http://www.cdc.gov). (2010).