Controlling growth Flashcards
List factors that affect growth of microbes
availability of nutrients, Moisture, Temperature, pH, Osmotic pressure, Atmospheric pressure, gaseous environment
Generation time
time it takes for one cell to divide into two cells (so population is doubled)
Selective media
discourages growth of some organisms and encourages the growth of others
Differential media
allows you to differentiate between organisms growing on the media.
Sterilisation
destruction/elimination of all microbes
disinfection
the elimination of most or all pathogens (except endospores) from non-living objects
Sanitisation
reduction of microbes to level considered safe by public health standards
List some physical methods to inhibit microbe growth
Heat – boiling, burning, pasteurisation, autoclave, Desiccation (drying), Radiation – gamma radiation & UV light, Filtration
Cleaning – hand washing (mechanical removal)
Disinfectants
chemicals used to kill microbes on inanimate objects
antiseptics
chemicals used to disinfect skin and other living tissue
Microbicidal agents
chemical agents that kill microbes e.g disinfectant, antiseptic
Microbiostatic
inhibit growth of microbes but don’t necessarily kill them e.g. food additives
Sepsis
presence of pathogens in blood or tissue
Asepsis
absence of pathogens
Aseptic techniques
a collection of techniques that are used to prevent contamination by eliminating and
excluding pathogens. e.g. suturing wounds, using clean equipment
Sterile techniques
are techniques that are used to eliminate ALL microbes from a particular area e.g auto claves to sterilise equipment
