第七章 微生物的控制.pptVIP

Contents 7.1 Overview of Microbial Control 7.2 Methods of Physical Control 7.3 Chemical Agents in Microbial Control 7.1 Overview of Microbial Control 1. Categories of Microbial Control Physical agents Chemical agents Mechanical removal 2. Relative Resistance of Microbial Forms Highest resistance: bacterial endospores Moderate resistance: Protozoan cysts (胞、囊); some fungal sexual spores; some viruses (hepatitis B virus and the poliovirus. Naked viruses are more resistant than enveloped forms). Bacteria with more resistant vegetative cells: Mycobacterium tuberculosis (结核分枝杆菌), Staphylococcus aureus (金黄色葡萄球菌), Pseudomonas (假单胞菌) Least resistance: Most bacterial vegetative cells; fungal spores and hyphae; enveloped viruses; yeasts; protozoan trophozoites (营养体) 3. Terminology ① Sterilization Sterilization (灭菌) is a process that destroys or removes all viable microorganisms, including viruses. Sterile (无菌): Any material that has been subjected to this process is said to be sterile. This term has the strictest sense. An object cannot be slightly sterile or almost sterile-it is either sterile or not sterile. Most sterilization is performed with a physical agent such as heat ② Microbicidal Agents (微生物杀菌剂) The root -cide means to kill Bactericide-is a chemical that destroys bacteria except for those in the endospore stage Fungicide-is a chemical that can kill fungal spores, hyphae, and yeasts Virucide-is any chemical known to inactivate viruses, especially on living tissue Sporicide-is an agent capable of destroying bacterial endospores ③ Agents That Cause Microbistasis (微生物抑菌剂) Stasis (停滞) Microbes are temporarily prevented from multiplying but are not killed outright Bacteriostatic agents (细菌抑菌剂) prevent the growth of bacteria on tissues or on objects in the environment. Fungistatic chemicals (真菌抑制剂) inhibit fungal growth ④ Germicides, Disinfection, Antisepsis Germ: is a common term for a pathogenic microbe (致病菌) Germicide (杀菌剂，指致病菌), also called microbicide, is any chemica