Due to the different experimental methods, there are certain differences in the interpretation of the time of surface disinfectants to kill microorganisms. The same disinfectant product can use the suspension method, the carrier method, or even the mechanical simulation method, a simulation device that combines physical and chemical actions.
Under the same action time, the suspension method is easier to kill microorganisms. Because in this type of experiment, the experimental microorganisms are thrown into the surface disinfectant solution, that is, the microorganisms are completely immersed in the disinfectant solution. In the carrier method, the experimental microorganisms are dripped on the carrier in advance, and the disinfectant solution is dripped after it has dried up.
Therefore, it is conceivable that the microorganisms and the carrier are not in contact with the disinfecting solution. Therefore, in the carrier method, in a sense, the surface of the disinfectant solution in the test should directly contact microorganisms, and besides it also requires that the surfaces disinfectant solution can quickly penetrate between the microorganisms and the carrier and all microorganisms should be wiped out before the solution dries up.
It can be seen that under the same killing time, the experimental data of the carrier method can better support the conclusion that the disinfectant is suitable for disinfection on the surface. Therefore, when reading the microbiological test report, it is necessary to understand which experimental method the experimental results are based on.
A large number of studies have shown that the microbial contact time of the surface disinfectant used in hospitals in the 30s to 60s, which can reduce the pathogens that cause HAIs.
At present, most of the disinfectants registered in the US EPA have a contact time of 1 min to 2 min for killing pathogens known to cause HAIs and the outbreak of infection. This requires disinfectant manufacturers to shorten the contact time and quickly kill microorganisms to obtain the approval of the US EPA so that medical institutions can effectively kill pathogenic microorganisms in the environment during actual application.
Therefore, to examine whether a disinfectant can be used for environmental disinfection from a personal perspective, it is an important indicator to understand whether the disinfectant can kill pathogenic microorganisms within 1 min to 3 min.
Of course, the surface disinfectant kills microorganisms with a cumulative effect of time, that is, the microorganisms begin to die after tens of seconds of contact. With the extension of contact time, the number of deaths of microorganisms also increases, and at a certain time, the microorganisms are all "killed".
The standard bacteria usually used in the microbiology laboratory to carry out biological sterilization experiments are bacteria that grow in a controllable and good environment and are "clean" or "naked" bacteria. If there are pollutants, it can not only protect pathogenic microorganisms, but also prevent them from effectively or fully contacting environmental disinfectant so as to avoid being killed.
In addition, due to the different chemical components contained in the pollutants, some will neutralize the active ingredients of the disinfectant in the solution, and some may interfere with the active ingredients of the disinfectant, changing the sterilization mechanism, and resulting in a decline in the disinfection effect. Therefore, it is necessary to understand that the experimental microorganisms are "clean", but in actual use, the confronted microorganisms are protected by pollutants.
In order to ensure the consistency of the results tested in different laboratories, the experimenters not only use standard bacteria, that is, they come from the ATCC strain library, but also have the concept of "algebra" for the experimental bacteria used, which are neither the "old generation" that can be easily killed nor the "new generation" with strong resistance.
However, in the actual surface disinfection, most of the pathogenic microorganisms we face come from infected persons or colonized patients. And those bacteria which can survive on the surface of inanimate for a long time definitely cannot be killed easily and much attention should be paid to it! Therefore, numerous uncertain factors of different kinds of disinfectant spray must be taken into consideration.
When we apply disinfectant on the surface of the environment, a certain moisturizing time is required, and also the effective concentration of the disinfectant in the solution should be ensured because wipes and non-woven wipes have an adsorption effect on the effective ingredients of the disinfectant. In this way, the concentration of the disinfectant actually used on the surface will be lower than the concentration used in the experiment, and the actual disinfection effect will be greatly reduced.