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Chapter 7: The _______ of Microbial Growth Microorganisms and Microbial Growth
Figure 7.11
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Terminology Related to the __________ Microbial Growth
___________: Removal of all microbial life ___________: Removal of pathogens __________: Removal of pathogens from living tissue __________: Removal of microbes from a limited area Sanitization: Lower microbial counts on eating utensils _____________________: Kills microbes Bacteriostasis: Inhibiting, not killing, microbes
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Effectiveness of antimicrobial treatment depends on:
______ of microbes Environment: Ex. temperature ______ of exposure Microbial characteristics
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Microbial Control Agents
______________ Heat, Filtration, Low Temperature, Pressure, Dessication, Radiation Phenols, Chlorhexidine, ________, Halogens, Heavy Metals, Surface Active Agents Various Effects of Microbial Control Agents Alteration of membrane permeability Damage to proteins Damage to _____________ acids Microbial Control Agents
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Physical Method of Microbial Control: Moist Heat
Moist heat denatures proteins Autoclave: _______ under pressure Figure 7.2
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Physical Methods of Microbial Control: Dry Heat
Dry Heat Sterilization kills by ______________ ______________ Incineration Hot-air sterilization Hot-air Autoclave Equivalent treatments 170˚C, 2 hr 121˚C, 15 min
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Physical Methods of Microbial Control ______________
_____________ reduces spoilage organisms and pathogens Methods used in pasteurization: ____________________ High-temperature short-time 72°C for 15 sec Ultra-high-temperature: _______________ Thermoduric organisms survive
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_____Methods of Microbial Control cntd.
_____________ removes microbes _____________: inhibits microbial growth Refrigeration Deep freezing Lyophilization _________________ denatures proteins prevents metabolism causes plasmolysis ________________ damages DNA
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Physical Methods of Microbial Control ______________
Radiation damages _________ Types of radiation: Ionizing radiation (X rays, gamma rays, ____________) Nonionizing radiation (__) (___________ kill by heat; not especially antimicrobial)
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Chemical Methods of Microbial Control
Types of Disinfectants ___________ – disrupt plasma membranes Iodine, Chlorine, Bleach – _____________ agents _________ – denature proteins, dissolve lipids ________________ – denature proteins Peroxides – oxidizing agents Principles of effective disinfection ________________ of disinfectant Organic matter pH Time
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______ Methods of Microbial Control
Types of Disinfectants ___________ – disrupt plasma membranes Iodine, Chlorine, Bleach, Peroxides – ________ agents Alcohols – denature proteins, dissolve lipids Heavy metals – denature ____________ Principles of effective disinfection _______________ of disinfectant Organic matter pH Time ______ Methods of Microbial Control
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Types of Disinfectants
Surface-Active Agents or Surfactants __________ Degerming Acid-anionic _______________ Sanitizing Quarternary ammonium compounds Cationic detergents Bactericidal, Denature proteins, disrupt plasma membrane Evaluating a Disinfectant __________________ method
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FOOD PRESERVATION Chemical Food Preservatives
_________ Acids: sorbic acid, benzoic acid, calcium propionate Inhibit metabolism Control molds and bacteria in foods and cosmetics __________: prevents endospore germination __________: Nisin and natamycin prevent spoilage of cheese
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