FOOD SCIENCE ›› 2007, Vol. 28 ›› Issue (2): 169-173.

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Effects of Bacteria Concentration on Sterilization of Escherichia coli in High Pressure Process

HUANG  Xun-Duan, PAN  Jian, XIE  Hui-Ming, WANG  Hai-Xiang, YANG  Yi, WANG  Wu   

  1. 1.Institute of Bio-mechanical and Electrical Engineering, Hefei University of Technology, Hefei 230009, China; 2.School of Life Sciences, Anhui University, Hefei 230039, China
  • Online:2007-02-15 Published:2011-12-31

Abstract: In this experiment, effects of high pressure on Escherichia coli were studied and effects of bacteria concentration on lethal rate was highlighted by applying central composite design of response surface methodology.Based on the results,the model is established as y=81.26-8.3x1 + 29.3x2 + 5.5x3 + 7.7x4 + 11.2x1x2-1.4x1x3 + 3.4x1x4-5.4x2x3-4.8x2x4-1.4x3x4 + 0.5x12 -1.9x22 + 1.1x32-6.7x42. Analysis of variance showed that the model is feasible, so it could be used to analyse and predict the experiment. Bacteria concentration of sample is a significant factor in treatment and there is a significant interaction between bacteria concentration and pressure. Results showed that lethal rate decreases with bacteria concentration going up and increase with pressure going up. For example, to low bacteria concentration sample,low pressure could sterilize,while high bacteria concentration sample need high pressure to sterilize.Pressure,temperature and time are also significant factors for high pressure process.It is sugguested that proper parameters should be chosen according to bacteria concentrations in different samples so as to make high pressure sterilization more efficient and practical.

Key words: high pressure, Escherichia coli, bacteria concentration, letahal rate