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destroying all forms of microbal life


destroying pathogen & growing cells, but not spores and viruses


a chemical that quickly KILLS microbes but not necessary spores


inhibiting BACTERIAL growth but not killing the cells


the absence of pathogens from an object or area


the temporary removal of microbes


reducing pathogens to safe levels for the general public

opportunistic pathogen

CAUSES DISEASE under unusual conditions


the most common method used to kill microbes

thermal death point

the lowest TEMPERATURE required to KILL all the microbe in 10 minutes

thermal death time

the minimum TIME needed to KILL all microbes at a given TEMPERATURE

decimal reduction time

the time required for 90% to be killed at a certain temperature


passing through small pores


drying out

ionizing radiation

short wavelength high energy rays, react with water to form TOXIC oxygen molecules

nonionizing radiation

long wavelengths that damage DNA or heat water in cells


damages the cell membrane and proteins and kills everyting


damages the microbes cell, but not spores


[flourine, chlorine, bromine, iodine] react with H2O to form acids and damage amino & fatty acids


it kills bacteria and fungi but not spores or virus, by damaging membranes and proteins

heavy metals

high atomic WEIGHT elements [ag, hg, cu, zu] damage proteins

surface active agents

lower SURFACE tension and break membranes into tiny droplets

quaternary ammonium compounds

change cell permeability causing the cytoplasm to leak out


inhibits molds, are safe for humans


damage proteins, kill bacteria and viruses in minutes, kills spores in a few hours

gaseous chemosterilizers

denature proteins, kill all microbe and spores, but may cause CANCER

oxidizing agents

produce toxic OXYgen molecules and some spores

phenol coefficient test

compares the effect of a test chemical with phenol

dilution test

bacteria are added to serial DILUTIONS of the TEST chemical and the amount

filter paper

a piece of filter paper that has been soaked with the test chemical is placed on top of bacteria growing in a petri dish and the zone of inhibition is measured

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