Kinetics Of E.coli Sterilization By Heating Or SAEW In Sol State

Hydrosols have many advantages such as biological adhesion,biocompatibility and degradability.In the current food field,natural polymer hydrosols are rarely used.Generally,polysaccharides hydrosols are modified as food preservation packaging materials,food transportation refrigerants and food flavor substances embedding agents.Because of its high moisture retention and stable slow release,and the good biocompatibility and high safety of natural polymer hydrosols,it has a good application prospect in the food field.With the further research of intelligent controlled release and bacteriostatic hydrosols,it will provide certain technical support and theoretical basis for food preservation and functional food development.Slightly acidic electrolyzed water(SAEW)has the characteristics of instantaneous,broad-spectrum,high efficiency,safety and no residue.However,the effective chlorine component is easy to degrade.Therefore,it is necessary to find a way to delay the attenuation of effective chlorine and prolong the sterilization time.In order to explore the sterilization kinetics of heat or SAEW on E.coli in the sol state,the sterilization effect under different sol viscosity,different temperature,different time and different effective chlorine concentration was studied under the condition of convective heating system.The total number of colonies was taken as the index.The equation was used to fit the thermal sterilization kinetics and the effective chlorine decay kinetics equation.The conclusions of this study are as follows :(1)By analyzing the error factors and their statistical laws,it is found that the measurement error is greater than the dilution error in the process of detecting microorganisms by plate counting method.(2)Establish convective heating system.Based on the convective heating system,the relationship between the rotational speed of the peristaltic pump and the volume flux at different temperatures(25,52,53,54,55,56℃)was measured,which improved the accuracy and accuracy of controlling the thermal sterilization time of the hydrosol.(3)Based on the plate counting method and convective heating system,the effects of different hydrosol viscosity,different sterilization temperature and different sterilization time on the sterilization effect of Escherichia coli were discussed.The results showed that the total number of colonies decreased with the increase of temperature,time and available chlorine.The random kinetic equation(3-5)of thermal sterilization was used to fit and compare the thermal sterilization effect of different viscosity hydrosols.At the same sterilization temperature,the higher the viscosity of hydrosol,the smaller the sterilization kinetic parameter λ,indicating the lower the sterilization effect.In the sol state,viscosity is a factor affecting the thermal sterilization rate.(3)On the basis of plate counting method and convective heating system,the effects of different sol viscosity(26.38,44.58,441.90 m Pa·s),different sterilization time(1,2,3,4,5,6,7,8,9,10min)and different available chlorine concentration(5.70,7.16,9.45,12.50 mg / L)on the bactericidal effect of Escherichia coli were investigated.The results showed that the total number of colonies decreased with the prolongation of time and the increase of available chlorine.The available chlorine decay kinetic equation(3-6)and the bactericidal kinetic equation(3-7)were used to analyze and compare the bactericidal effect of SAEW hydrosols with different viscosities.The k ’ reaction ACC decay rate.During the sterilization process of SAEW hydrosol,the higher the sol viscosity,the smaller the available chlorine decay parameter k ’,indicating that the slower the available chlorine decay,the lower the sterilization rate,and the longer the sterilization time.The hydrosol has a certain sustained release effect on the available chlorine of slightly acidic electrolyzed water.In summary,the sterilization rate of E.coli by hot or slightly acidic electrolyzed water SAEW in the sol state will decrease.The sol can release the available chlorine in slightly acidic electrolyzed water and prolong the sterilization time,which can provide a basis for the sterilization and preservation of food.