Final answer:
The effectiveness of a disinfectant is primarily determined by its concentration and contact time, with other factors including temperature and pH also playing a role. Historically, effectiveness was compared to phenol, but now various testing methods, like the use-dilution test, are used.
Step-by-step explanation:
The ability of a disinfectant to perform correctly depends primarily on its concentration and contact time. Factors such as the length of exposure to the disinfectant are critical since longer exposure tends to increase efficacy. Moreover, the concentration of the disinfectant is also crucial, as higher concentrations are generally more effective than lower ones. Other environmental conditions that can influence the potency of a disinfectant include temperature, pH, the presence of organic matter, and whether the targeted microorganisms are inclined to resist the disinfecting agent. Choosing the correct protocol requires consideration of these variables to control microbial growth effectively.
Historically, the effectiveness of chemical disinfectants has been compared with that of phenol, using the phenol coefficient method, although this is no longer commonly used. The use-dilution test is another method that determines a disinfectant's effectiveness on surfaces by checking for the survival of bacteria after exposure to the disinfectant at various concentrations and time intervals.