Prediction of Growth of Escherichia coli O157 : H7 in Lettuce Treated with Alkaline Electrolyzed Water at Different Temperatures

  • Ding, Tian (Department of Food Science and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University) ;
  • Jin, Yong-Guo (College of Food Science and Technology, Huazhong Agricultural University) ;
  • Rahman, S.M.E. (Department of Food Science and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University) ;
  • Kim, Jai-Moung (Department of Food Science and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University) ;
  • Choi, Kang-Hyun (Department of Food Science and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University) ;
  • Choi, Gye-Sun (Department of Clinical Research Division Food & Drug Administration) ;
  • Oh, Deog-Hwan (Department of Food Science and Biotechnology and Institute of Bioscience and Biotechnology, Kangwon National University)
  • Published : 2009.09.30

Abstract

This study was conducted to develop a model for describing the effect of storage temperature (4, 10, 15, 20, 25, 30 and $35^{\circ}C$) on the growth of Escherichia coli O157 : H7 in ready-to-eat (RTE) lettuce treated with or without (control) alkaline electrolyzed water (AIEW). The growth curves were well fitted with the Gompertz equation, which was used to determine the specific growth rate (SGR) and lag time (LT) of E. coli O157 : H7 ($R^2$ = 0.994). Results showed that the obtained SGR and LT were dependent on the storage temperature. The growth rate increased with increasing temperature from 4 to $35^{\circ}C$. The square root models were used to evaluate the effect of storage temperature on the growth of E. coli O157 : H7 in lettuce samples treated without or with AIEW. The coefficient of determination ($R^2$), adjusted determination coefficient ($R^2_{Adj}$), and mean square error (MSE) were employed to validate the established models. It showed that $R^2$ and $R^_{Adj}$ were close to 1 (> 0.93), and MSE calculated from models of untreated and treated lettuce were 0.031 and 0.025, respectively. The results demonstrated that the overall predictions of the growth of E. coli O157: H7 agreed with the observed data.

본 연구는 오염된 양상치를 알카리전해수로 세척한 처리구와 비처리구에 오염된 E. coli O157 : H7균이 다양한 온도 (4, 10, 15, 20, 25, 30, $35^{\circ}C$)에 저장할 경우 이균의 specific growth rate (SCR) 과 lag time (LT) 생육변수에 미치는 영향을 조사하기 위한 모델을 개발하기 위하여 수행되었다. E. coli O157 : H7의 specific growth rate (SGR) 과 lag time (LT)를 결정하기 위해 생육도를 Gompertz 식을 사용하여 fitting한 결과, $R^2$값이 0.994로 나타났다. 실험값으로부터 얻은 SGR과 LT는 저장온도에 의존하는 것으로 나타났으며 $4^{\circ}C$에서 $35^{\circ}C$까지 온도가 증가할수록 성장 속도가 증가하는 것으로 나타났다. AIEW 처리구 또는 비처리구의 양상치 에서 E. coli O157 : H7의 성장 kinetics에 대한 저장 온도의 효과를 평가하기 위해 SRG에 대한 두개의 모델을 개발하였다. 유도된 2개의 모델 검증은 $R^2$, $R^2_{Adj}$ (adjusted determination coefficient) 및 MSE (mean square error)를 적용하였으며, 그 결과 $R^2$, $R^2_{Adj}$가 1 (>0.93)에 근접하였으며, 알카리 전해수 처리구 및 비처리구 양상치 모델의 MSE는 각각 0.031, 0.025로 나타났다. 따라서, 본연구에서 개발된 모델의 생육변수는 실험 치에서 얻은 E. coli O157 : H7의 생육변수 결과와 매우 유사한 것으로 나타났다.

Keywords

References

  1. Abadias, M., Usall, J., Oliveira, M., Alegre, I., Vinas, I.: Efficacy of neutral electrolyzed water (NEW) for reducing microbial contamination on minimally-processed vegetables. Int. J. Food Microbial. 123, 151-158 (2008) https://doi.org/10.1016/j.ijfoodmicro.2007.12.008
  2. Chang, J.M., Fang, T.J.: Survival of Escherichia coli O157 : H7 and Salmonella enterica serovars Typhimurium in iceberg lettuce and the antimicrobial effect of rice vinegar againstE. coli O157:H7.Food Microbiol. 24,745-751 (2007) https://doi.org/10.1016/j.fm.2007.03.005
  3. Beuchat, L.R.: Pathogenic microorganisms associated with fresh produce. J. Food Prot. 59,204-216 (1996)
  4. Ackers, M.L., Mahon, B.E., Leahy, E., Goode, B., Damrow, T., Hayes, P.S., Bibb, W.F., Rice, D.H., Barrett, T.J., Hutwagner, L., Griffin, P.M., Slutsker, L.: An outbreak of Escherichia coli O157:H7 infections associated with leaf lettuce consumption. J. Infect. Dis. 177, 1588-1593 (1998) https://doi.org/10.1086/515323
  5. CDC: Outbreak of Escherichia coli O157:H7 infections among boy scouts in Maine. EPI-AID 95-93 (1995)
  6. Koseki, S., Yoshida, K., Kamitani, Y., Isobe, S., Hoh, K.: Effect of mild heat pre-treatment with alkaline electrolyzed water on the efficacy of acidic electrolyzed water against Escherichia coli O157:H7 and Salmonella on Lettuce. Food Microbiol. 21, 559-566 (2004) https://doi.org/10.1016/j.fm.2003.11.004
  7. Park, C.M., Hung, Y.C., Doyle, M.P., Ezeike, G.O.L, Kim, C.: Pathogen reduction and quality of lettuce treated with electrolyzed oxidizing and acidified chlorinated water. J. Food Sci. 66, 1368-1372 (2001) https://doi.org/10.1111/j.1365-2621.2001.tb15216.x
  8. Miyashita, K., Yasuda, M., Ota, T., Suzuki, T.: Antioxidative activity of a cathodic solution produced by the electrolysis of a dilute NaCl solution. Biosci. Biotechnol. Biochem. 63,421-423 (1999) https://doi.org/10.1271/bbb.63.421
  9. Bang, W.S., Chung, H.J., Jin, S.S., Ding, T., Hwang, L.G, Woo, G.J., Ha, S.D., Bahk, G.J., Oh, D.H.: Prediction of Listeria monocytogenes growth kinetics in sausages formulated with antimicrobials as a function of temperature and concentrations. Food Sci. Biotechnol.17, 1316-1321 (2008)
  10. McMeekin, T.A., Brown, J., Krist, K., Miles, D., Neumeyer, K., Nichols, D.S., Olley, J., Presser, K., Ratkowsky, D.A., Ross, T., Salter, M., Soontranon, S.: Quantitative microbiology: a basis for food safety. Emerg. Infect. Dis. 3,541-550 (1997) https://doi.org/10.3201/eid0304.970419
  11. Whiting, R.C.: Microbial modeling in foods. Crit. Rev. Food Sci. Nutr. 35,467-494 (1995) https://doi.org/10.1080/10408399509527711
  12. Fujikawa, H., Kai, A., Morozumi, S.: A new logistic model for Escherichia coli growth at constant and dynamic temperatures. Food Microbiol. 21, 501-509 (2004) https://doi.org/10.1016/j.fm.2004.01.007
  13. Ratkowsky, D.A., Olley, J., McMeekin, T.A., Ball, A.: Relationship between temperature and growth rate of bate rial cultures. J. Bacteriol. 149, 1-5 (1982)
  14. Ratkowsky, D.A., Lowry, R.K., McMeekin, T.A., Stokes, A.N., Chandler, R.E.: Model for bacterial culture growth rate throughout the entire biokinetic temperature range. J. Bacteriol. 154,1222-1226 (1983)
  15. Ozer, N.P., Demirci, A.: Electrolyzed oxidizing water treatment for decontamination of raw salmon inoculated with Escherichia coli O157:H7 and Listeria monocytogenes Scott A and response surface modeling. J. Food Eng. 72,234-241 (2006) https://doi.org/10.1016/j.jfoodeng.2004.11.038
  16. Erkmen, O.: Modeling the effects of sucuk production technique on Listeria monocytogenes, aerobic bacteria and lactic acid bacteria during ripening and storage. Food Bioprod Process. 86, 220-226 (2008) https://doi.org/10.1016/j.fbp.2007.10.002
  17. Koseki, S., Isobe, S.: Growth of Listeria monocytogenes on iceberg lettuce and solid media. Int. J. Food Microbiol. 101, 217-225 (2005) https://doi.org/10.1016/j.ijfoodmicro.2004.11.008
  18. McMeekin, T.A., Olley, J., Ross, T., Ratkowsky, D.A.: Predictive Microbiology: Theory and Application. Research Studies Press, Taunton (1993)
  19. Koseki, S., Isobe, S.: Prediction of pathogen growth on iceberg lettuce under real temperature history during distribution from farm to table. Int. J. Food Microbiol. 104,239-248 (2005) https://doi.org/10.1016/j.ijfoodmicro.2005.02.012
  20. Gao, Y.L., Ju, X.R., Jiang, H.H.: Analysis of reduction of Geobacillus stearothermophilus spores treated with high hydrostatic pressure and mild heat in milk buffer. J. Bacteriol. 125,351-360 (2006) https://doi.org/10.1016/j.jbiotec.2006.03.004
  21. Adair, C., Kilsby, D.C., Whittall, P.T.: Comparison of the Schoolfield (non-linear Arrhenius) model and the square root model for predicting bacterial growth in foods. Food Microbial. 6,7-18 (1989) https://doi.org/10.1016/S0740-0020(89)80033-4