BIO-183 Lecture Notes - Lecture 9: Corrosion, Thermal Death Time, Clostridium
Document Summary
Antisepsis/degermation- removing number of microbes on human skin, form of decontamination but on living tissues. Decontamination-inanimate objects: destroys vegetative pathogens but not bacterial endospores. Sterilization- destroys or removes all viable micro-organisms (including viruses)- includes bacterial endospores: surgical instruments, syringes, commercially packaged food, autoclave: high pressure steam and temperatures. Dry heat: complete incineration of microorganisms 160-1000s of degrees c- hotter than moist heat. Moist heat: boiling water/steam- 60-135 degrees c- not as hot as dry heat. Pasteurization- use of heat to kill microorganisms (ex: milk pasteurization) Death: permanent termination of an organism"s vital process. Active cells die more quickly than less metabolically active cells (ex: bacterial endospores much harder to kill) Thermal death time (tdt)- shortest length of time required to kill all test microbes at a specified temperature. Thermal death point (tdp) refers to the temperature. Kill via desiccation, die and dehydrate at room temperature: psycoldphiles- staph , salmonella. Filtration: membrane with holes too small for bacteria to fit through.
