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Related Flashcards
Cards In This Set
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What is an antimicrobial agent?
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Treatments and substances that kill or inhibit microorganisms
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What are some physical antimicrobial agents?
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Heat, drying or desiccation, radiation
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What are some chemical antimicrobial agents?
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Detergents, solvents, oxidizing agents, heavy metals
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What is the difference between bacteriocidal and bacteriostatic?
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Bacteriocidal kills bacteria, whereas bacteriostatic only slows or stops its growth
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Why would you want to use a bacteriostatic agent instead of a bacteriocidal agent?
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A bacteriocidal agent could destroy the product you are protecting from bacteria. A bacteriostatic will slow growth without damaging the product.
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Factors that affect efficiency of a Bacteriocidal treatment are?
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Material, i.e. metal vs food
age, species, population size of bacteria
storage temperature, pH, osmotic pressure, organic matter of the product
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Relative susceptibilities of microbes to antimicrobial agents are?
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Picture
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What are some different methods of sterilization for different materials?
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Glassware - steam in autoclave
petri plates - poisonous gas
heat sensitive vitamins - filtration
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What is the effect of bacterial population size on sterilization efficiency?
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 Graph |
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What is the effect of pH on efficiency of Pasteurization?
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 Graph |
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How does an antimicrobial treatment kill the bacteria?
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By destroying or damaging a vital cell structure or by inhibiting some vital metabolic reaction
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How does heat kill a bacterial cell?
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By denaturing proteins and nucleic acids
denatured proteins tend to coagulate into an insoluble mass
heat also disrupts cell membrane structure
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Which is faster: moist heat or dry heat? why?
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Moist heat because heat energy is transferred from the environment into the cell faster due to the high heat capacity of water
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Protein denaturization by heat
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Breaks up structure
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Which is hotter: compressed steam or boiling water?
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Compressed steam
use this to heat sample to higher temperature
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