Microbial growth control Flashcards
Decontamination?
- Treatment of an object surface to make it “safe to handle”
* E.g. wiping table after meal
Disinfection?
- A chemical or physical agent that directly targets pathogens are used
- E.g. Sodium hypochlorite (Bleach)
Sterilization?
• Killing or removal of “all” viable organisms
Heat sterilization?
• Affects the structure of macromolecules
Radiation sterilization?
• Altering and disrupting biopolymers such as DNA and protein
Filter sterilization?
• The pores of the filter are too small to allow bacteria to pass
Heat sterilization?
At very high temperatures, virtually all macromolecules lose their structure and their ability to
function
• This is called denaturation
Reduction time?
Decimal reduction time
• The time required for a 10-fold reduction in the
viability of a microbial population
Thermal death time
• The time required to kill all cells of a microbial
population at a specific temperature
Endospores?
Endospores are able to survive heat
• Much longer decimal reduction
time than vegetative cells
Water is important for successful autoclaving
• Dry cells and endospores are more
heat-resistant than moist objects
To define sterile?
Def: ”Less than 1 bacterium/endospore
per 1.000.000 objects”
Less than 1 bacterium/endospore
per 1.000.000 objects
Chemical antimicrobial control?
Antimicrobial agent
• A natural or synthetic chemical that kills or
inhibit growth of microorganisms
Different types of agents
• -cidal agents kill microorganisms
• -static agents inhibit the growth of microorganisms
Alcohols?
Denaturation of bacterial proteins
• Enter the cell and make intracellular proteins to lose
their structure and by that their function
The alcohol-concentration should not be too high
• Proteins of the cell-wall denaturate ”too quickly”
o Prevent the alcohol to penetrate further into the cell
o The bacteria can survive
