上 泽充通大学 Shanghai Jiao Tong University Lecture 6-1 Microbial Growth Control in vitro and in vivo Chapter 26 in Brock's Biology of Microorganisms Chen Feng School of Life Science and Biotechnology Shanghai Jiao Tong University http://micro.sjtu.edu.cn
Lecture 6-1 Microbial Growth Control in vitro and in vivo Chen Feng School of Life Science and Biotechnology Shanghai Jiao Tong University http://micro.sjtu.edu.cn Chapter 26 in Brock’s Biology of Microorganisms
上泽充通大学 Shanghai Jiao Tong University Why do we need growth control? Growth of unwanted bacteria Outside our body:Food spoilage-growth of bacteria in our food,e.g.milk,would deplete nutrition. Inside our body:Infectious disease-growth of bacteria within our body would cause health problems Shanghai Jiao Tong University
Shanghai Jiao Tong University Why do we need growth control? Growth of unwanted bacteria • Outside our body: Food spoilage-growth of bacteria in our food, e.g. milk, would deplete nutrition. • Inside our body: Infectious disease-growth of bacteria within our body would cause health problems
上泽充通大￥ Shanghai Jiao Tong University Definition of Some Terms ©Decontamination净化，去污 Treatment that renders an object or inanimate surface safe to handle 国Disinfection消毒 The process of eliminating nearly all pathogens,but not all microorganisms,from a object or habitat @Sanitization卫生处理 Closely related to disinfection.The microbial population is reduced to levels that are considered safe by public health standards. @Sterilization杀菌 The killing or removal of all living organisms and the viruses from a object or habitat. Shanghai Jiao Tong University
Shanghai Jiao Tong University Definition of Some Terms Decontamination净化,去污 • Treatment that renders an object or inanimate surface safe to handle Disinfection消毒 • The process of eliminating nearly all pathogens, but not all microorganisms, from a object or habitat Sanitization卫生处理 • Closely related to disinfection. The microbial population is reduced to levels that are considered safe by public health standards. Sterilization杀菌 • The killing or removal of all living organisms and the viruses from a object or habitat
上泽充通大￥ Shanghai Jiao Tong University Growth control Prevent growth of unwanted microorganisms ·Inhibition--limiting microbial growth抑菌 Cells maintain integrity-reversible 。 Sterilization-the killing or removal of all viable organisms from a growth medium杀菌 Cells lose their structural integrity-irreversible Agents for growth control o Bacteriostatic agents:inhibit bacterial growth抑菌剂 ·Bactericidal agents:destroy or kill bacteria杀菌剂 Shanghai Jiao Tong University
Shanghai Jiao Tong University Growth control Prevent growth of unwanted microorganisms • Inhibition-limiting microbial growth抑菌 • Cells maintain integrity-reversible • Sterilization-the killing or removal of all viable organisms from a growth medium杀菌 • Cells lose their structural integrity-irreversible Agents for growth control • Bacteriostatic agents: inhibit bacterial growth抑菌剂 • Bactericidal agents: destroy or kill bacteria杀菌剂
上降文通大学 Shanghai Jiao Tong University Methods of Growth Control in vitro ©Physical means ·Heat sterilization热力杀菌 ·Radiation sterilization放射杀菌 ·Filter sterilization:过滤除菌 ©Chemical means ·Antiseptics防腐剂 ·Disinfectants消毒剂 0 Sterilants杀菌剂 Shanghai Jiao Tong University
Shanghai Jiao Tong University Methods of Growth Control in vitro Physical means • Heat sterilization热力杀菌 • Radiation sterilization放射杀菌 • Filter sterilization过滤除菌 Chemical means • Antiseptics防腐剂 • Disinfectants消毒剂 • Sterilants杀菌剂
上游充通大学 Shanghai Jiao Tong University I.Physical Antimicrobial Control 6.1 Heat Sterilization 6.2 Radiation Sterilization 6.3 Filter Sterilization Shanghai Jiao Tong University
Shanghai Jiao Tong University I. Physical Antimicrobial Control 6.1 Heat Sterilization 6.2 Radiation Sterilization 6.3 Filter Sterilization
上泽充通大￥ Shanghai Jiao Tong University 6.1 Heat sterilization热力杀菌 High temperatures can influence growth Denaturation at high temperature:the lose of structure and ability to function of macromolecules高温使大分子变性 Proteins are the most heat sensitive macromolecules.Its higher order structures will be effected first蛋白质对热最 不稳定，其高级结构最先改变 Shanghai Jiao Tong University
Shanghai Jiao Tong University 6.1 Heat sterilization 热力杀菌 High temperatures can influence growth • Denaturation at high temperature: the lose of structure and ability to function of macromolecules 高温使大分子变性 • Proteins are the most heat sensitive macromolecules. Its higher order structures will be effected first蛋白质对热最 不稳定, 其高级结构最先改变
上泽充通大￥ Shanghai Jiao Tong University Heat sterilization is the most widely used method of controlling microbial growth High temperatures denature macromolecules Some bacteria produce resistant cells called endospores Can survive heat that would rapidly kill vegetative cells Shanghai Jiao Tong University
Shanghai Jiao Tong University Heat sterilization is the most widely used method of controlling microbial growth • High temperatures denature macromolecules Some bacteria produce resistant cells called endospores • Can survive heat that would rapidly kill vegetative cells
上泽充通大￥ Shanghai Jiao Tong University 6.11 Kinetics of heat sterilization Death from heating is an exponential.热致死是指 数形式的 The higher the temperature,the quicker the killing The time taken for a definite fraction(for example, 90%)of the cells to be killed is independent of the initial concentration.杀死指定比例（如90%）的微 生物所需时间与最初的微生物浓度无关 Shanghai Jiao Tong University
Shanghai Jiao Tong University 6.1.1 Kinetics of heat sterilization Death from heating is an exponential. 热致死是指 数形式的. • The higher the temperature, the quicker the killing The time taken for a definite fraction (for example, 90%) of the cells to be killed is independent of the initial concentration.杀死指定比例(如90%)的微 生物所需时间与最初的微生物浓度无关
上降充通大￥ Shanghai Jiao Tong University Important term of heat sterilization decimal reduction time(D)十倍致死时间 The time required for a ten fold reduction in the population density at a given temperature Determination of D:Viable counting Shanghai Jiao Tong University
Shanghai Jiao Tong University decimal reduction time (D)十倍致死时间 • The time required for a ten fold reduction in the population density at a given temperature • Determination of D: Viable counting Important term of heat sterilization