Microbial Growth Control Flashcards
Physical control methods
Heat Autoclaving Pasteurization Filter Cold Desiccation High osmotic pressure Radiation
Factors influence effectiveness of chemical control
Dilution
Time
pH
Organic matter
Types of disinfectants
Phenol Halogens Heavy metals Alcohol Surface active agents Quats Aldehydes (PHHASQuAl)
Removal of all microbial life
Sterilization
Killing c. Botulinium
Commercial sterilization
Removal or pathogens
Disinfection
Removal of pathogens from LIVING TISSUE
antisepsis
Lower microbial counts on utensils
Sanitation
Removal of microbes from LIMITED AREA
Degerming
Kills microbes
Biocide / germicide
INHIBITING microbes
Bacteriostasis
Use light for metabolism
Have chlorophyll
Use carbon dioxide and oxygen - main byproduct
Organic products
Phototrophs
Use hydrogen and sulfur
Chemotrophs
Needs oxygen
Increase o2
Decrease co2
Aerobic
Needs less oxygen
Decrease o2
Increase co2
Anaerobic
Time required for a bacteria to grow and divide
Generation time
Depicts how a bacteria behaves in a certain medium
Growth curve
Growth curve phases
Lag
Log
Stationary
Decline
Effectiveness of antimicrobial depends on
Characteristics of microbe Number of microbe Environment Time of exposure (C-NET)
Lowest temp at which all cells in a culture are killed in 10mins
Thermal death point
Time to kill all cells in a culture
Thermal death time
Minutes to kill 90% of a population at a given temp
Decimal reduction time
Effect of moist heat
Protein denaturation
Autoclaving
Moist heat Steam under pressure 15mins 121C 15psi
Pasteurization
63c for 30 mins
73c for 15 sec
140c for 1 sec
Reduce spoilage
Pasteurization
Kills by oxidation
Dry heat sterilization
Hot air sterilization
170c for 2hrs
Removes microbes by trapping in filter
Filtration