The Effect Of Carbohydrate On Thermal Resistance Of Gebacillus Stearothermophilus

Microbes are the main factors influencing the shelf life of food product.In order to improve food quality and extend food storage most products still use the traditional thermal sterilization technology in China's food industry.With the development of food industry,a series of new sterilization technology were developed by many scholars both at home and abroad,such as ionizing radiation sterilization,microwave sterilization,ultrahigh pressure processing and pulsed electric field sterilization.However,with the advantages of mature technology and high safety factor,thermal sterilization is still the most widely used method in food product enterprises.Most meat products are contaminated in the process by some non-pathogenic bacillus,thermophilic bacteria and high temperature resistant microbial,so these thermopiles and strong heat-resistant spore,such as Geobacillus stearothermophilus and its spore,will still remain in the product,even after thermal sterilization.In order to destroy the thermophiles and spore completely,strong heat treatment is needed theoretically,which may cause the damage of color,quality,structure and nutrition of meat product easily.So pasteurization and heat sterilization under 100? are popular in domestic meat product enterprises.Besides,the effect of thermal sterilization towards bacillus is closely related with heating environment.In order to study the thermal inactivation regularity of Geobacillus stearothermophilus ATCC7953 in different medium.The vaccinated 107 CFU/g Geobacillus stearothermophilus ATCC7953 were added in different medium(glucose,sucrose,starch),then subjected to thermal treatment.The surviving cell number was counted on selective media.The heat tolerance of Geobacillus stearothermophilus was analyzed by one-way ANOVA.Dose Resp model was used to fit the thermal inactivation curve by Curve Expert software.in order to systematically establish the theory system of the effect of carbohydrate on thermal resistance of Geobacillus stearothermophilus,and provide better theoretical basis for the optimization of thermal sterilization conditions in actual meat product process.The results showed that:(1)The inactivation regularity of Geobacillus stearothermophilus ATCC7953 experienced the same at three different center temperatures of 70?,80? and 90?.Before reaching the center temperature,the concentration decreased to a nearly constant value,and the concentration remained nearly constant with the heating time extending to 60 minutes,lethality rate of 98% or more,there are still cell residues Besides,the Exponential model were modeled by inactivation curves during thermal processing.(2)Geobacillus stearothermophilus ATCC7953 was used as the research object,with concentration of 2%,4%,6%,8%,10% glucose solution for heat-treatment medium,70?,80?,90? were set as three center temperatures.Before reaching the center temperature and at the time of 60 minnutes after reaching the center temperature,6% glucose could improve the heat resistance of Geobacillus stearothermophilus significantly.(3)With concentration of 2%,4%,6%,8%,10% sucrose solution for heat-treatment medium,before reaching the center temperature of 0-150 s heat treatment stage and at the time of 60 minnutes after reaching the center temperature,in the 70 ?,80 ?,90 ? three temperature conditions,10% and 25% sucrose could improve the heat resistance of Geobacillus stearothermophilus significantly.(4)With concentration of 2%,4%,6%,8%,10% starch solution for heat-treatment medium,before reaching the center temperature,4%?6%?8% and 10% starch could improve the heat resistance of Geobacillus stearothermophilus significantly.And after the central temperature to continue to heat treatment to 60 min,4%?8% and 10% starch could improve the heat resistance of Geobacillus stearothermophilus significantly and 10% of the starch effect is most significant.