In today ‘ s era of focus on health and hygiene, UV disinfection is widely used as an easy means of disinfection. However, there is a mistaken belief that UV disinfection has the same effect on all pathogens. This misunderstanding needs to be corrected so that together we can explore in depth the truth about UV disinfection.
The principle of UV sterilisation is to use specific wavelength UVs to destroy the nucleic acid structure of pathogens and deprive them of their reproductive and pathogenic capacity. Of these, UVCs, with a wavelength of 253.7 nm, have the most significant effects. But the sensitivity of different pathogens to UV is quite different.
Look at bacteria first. For example, coliform is a common intestinal bacteria that is sensitive to ultraviolet light. The nucleic acid will be quickly destroyed and killed in a relatively short period of time under a certain intensity of UV. However, it is quite different in the case of nodules. The nodule branch bacterium cell wall is rich in special components such as lipid, which are, to some extent, resistant to UV attacks and make it more resistant to UV. Even under the same UV irradiation conditions, the nodule branch bacterium survives much longer than the coli, requiring higher intensity or longer UV irradiation to be effective.
With regard to viruses, the difference is equally significant. Influenza viruses are relatively sensitive to UV and can be relatively quickly neutralized by routine UV disinfection equipment. However, polio virus resistance is stronger, its particle structure is more stable and UV penetrators and nucleic acids are more difficult to penetrate, so a stronger UV dose is needed to achieve effective disinfection.
Fungi is no exception. A fungus such as the white pyrophilus, in UV exposure, due to the complexity of its cell structure and composition, including the thickness of the cell wall, the distribution of cells in the cell, etc., reacts to UV at a slower rate than bacteria and viruses, requiring sustained UV exposure and a sufficient dose to achieve better disinfection.
There are also special pathogens, such as sprouts. The sprouts are hibernations formed by certain bacteria in harsh conditions and have great resistance. For example, the sprouts of Bacillus, which are protected by multiple layers of sprouts and sprouts on the outer layer, are tightly wrapped into the inner core structure. It is difficult for UVs to penetrate these barriers to damage their core genetic material, so UVs have very limited sterilisation effects on sprouts and often require a combination of other disinfection methods, such as high temperature and high pressure treatment, to be completely eliminated.
In the hospital wards, it is far from sufficient to control the spread of all pathogens if they rely solely on UV disinfection. For a number of pathogens that are less UV sensitive, such as the above-mentioned nodule streptococcus and the polio virus, it is possible to survive in the UV-sterilised “sews” and thus trigger cross-infection. In food-processing workshops, while UV can be used to disinfect air and object surfaces, the risk of food contamination remains for some UV-resistant micro-organisms without other means of disinfection, such as chemical disinfectant scrubbing, cleaning, etc.
Since UV sterilisation is not equally effective for all pathogens, how can UV sterilisation be reasonably applied? In the family environment, UV disinfection can be used as an aid to routine air and surface disinfection of some objects. For example, regular UV exposures to spaces such as bedrooms, living rooms, etc., are carried out with care to control the timing and intensity of exposure, while avoiding exposure to UV lamps. In public places, such as school classrooms, libraries, etc., UV disinfection equipment can be activated to disinfect the indoor environment during no-man ‘ s time, but there is also a need for a combination of disinfection and so forth for items that are frequently exposed, such as tables and chairs, door handles, etc. For medical sites, UV disinfection should be used in a targeted manner based on a risk assessment of pathogens in different regions and in coordination with other disinfection methods, such as high-temperature sterilisation of medical devices, chemical disinfectant leaching, etc., to ensure the complete and effective decontamination.
In short, UV sterilisation is not a panacea, and we need to properly understand the differences in its sterilisation effects on different pathogens and use this disinfection technique in a rational way to better safeguard our health and safety.
