CHEMICAL CONTROL METHODS USUALLY ARE INTENDED FOR DISINFECTION AND ANTISEPSISChemical control methodsgenerally do not achieve sterile conditions, although a few do. The principle applications of chemicals are disinfection and antisepsis. Several tests are available for evaluating the effectiveness of disinfectants and antiseptics.Phenol coefficientDisk diffusionUse dilution
THE PHENOL COEFFICIENT TEST COMPARES THE EFFECTIVENESS OF THE AGENT TO PHENOLPhenol is the oldest chemical control agent, having been introduced into use by Joseph Lister in the 19thcentury.The phenol coefficient testcompares the killing efficiency of the agent to phenol.Identical amounts of Staphylococcus aureus or Salmonella typhi are added to each tube. Samples are withdrawn and the concentration at which all test bacteria are killed after 10 minutes but not after 5 minutes are determined.