Chapter 7 - Control of Microbial Growth Flashcards
(29 cards)
Sterilization
Removal of all bacterial life
Commercial Sterilization
Applying enough heat to destroy the endospores of Clostrididium Botulinum (Botulism)
Disinfection
- Removal of pathogens
- ex: Steam, Chemicals, UV, Boiling Water
Antisepsis
Removal of pathogens from living tissue
Degerming
Mechanism of removal of microbes rather than killing the microbes
Sanitization
Lowers the microbial counts on a surface
Biocides/Germicides
Kills microbes
Bacteriostatic
Inhibits growth of bacteria but leaves microbes where they are
Microbial Death Rate
- Exponential
- Linear when logarithmic
Effectiveness of Antimicrobial Treatments
- Dose dependent
- Number of Microbes
- Environmental Influences
- Time of Exposure
- Type of Microbe
Antimicrobial Targets
- Plasma Membrane
- Essential Proteins
- Nucleic Acids
Thermal Death Point
The lowest temperature at which all cells in a culture are killed within 10 minutes
Thermal Death Time
Time needed to kill all cells in a culture at a given temperature
Decimal Reduction Time
Minutes it takes for 90% of the population to be killed at a given temperature
Pasteurization
Eliminates pathogens and spoilage organisms
Moist Heat
Kills by denaturing proteins
Dry Heat
Kills by oxidation
Filtration
Separates microbes without the use of heat
Low Temperature
- Inhibits microbial growth does not kill
- Refrigeration, Deep Freezing
High Pressure
Denatures proteins and carbohydrates
Desiccation
Absence of water, prevents metabolism (freeze drying)
Osmotic Pressure
Creates a hypertonic environment to desiccate the microbe
Radiation
Damages DNA
Effectiveness of Disinfectant
- Concentration of Disinfectant (higher is better)
- Extraneous Organic Matter (Inhibits)
- pH (lower is better)
