|Common Disinfection Methods
Common disinfection methods: physical and chemical methods.
Physical methods: thermal disinfection, ultraviolet disinfection, ionizing radiation, microwave method. The most common physical disinfection methods are hot disinfection and UV disinfection.
Chemical methods: by chemical substances to kill pathogenic micro-organisms called chemical disinfected methods.
The ideal chemical disinfectant should include following conditions: 1. broad-spectrum, use of low concentration, quick; 2. stabilized nature, soluble water, used low temperatures; 3. less susceptible with organisms, acid, alkali and other factors; 4. non-corrosive to materials, colorless, odorless, easy to remove residual drug after disinfection; 5. non-toxic or low toxicity; 6. use of non-hazardous; 7. inexpensive, easy to transport, a large number of supply.
Over years passed, the researchers conducted extensive researching on disinfectants, so far still have not found any one to meet above conditions, but only chlorine dioxide disinfectant is the most desirable type among of the fourth generation currently. Development of Chemical Disinfectant and Classification
1.Up to now, in development of chemical disinfectant, there is a representative seperatly in different period. First phase is Formaldehyde. Second phasealf is Epoxy Alkane. Third phase is Glutaraldehyde, the latest generation is the chlorine dioxide.
2. Chemical Disinfectants Classification
According to chemical disinfectants on microbial disinfection effect, disinfectants can be divided into high, medium, low-efficiency for three categories.
High effective disinfectant can kill all microorganisms, including bacteria, fungi, virus, spore, for example, chlorine dioxide, glutaraldehyde, hydrogen peroxide, etc. Medium effective disinfectant can not kill bacteria spores, but can kill bacteria, fungi and most viruses, for example ethanol, chlorine preparations, coal and phenol soap solution. Low-effective disinfectant can kill most bacteria body, some fungi and viruses, but can not kill bacterial spores, mycobacterium tuberculosis and certain fungi and viruses, such as chlorhexidine, benzalkonium bromide.
Affected Disinfection Factors
1. The concentration of disinfectant: The basic conditions to kill micro-organisms include intensity and time of disinfection. Chemical disinfection sterilization intensity means used concentration of disinfection. The disinfection effect depends on disinfectant concentration and time.
2. The types and quantities of microbial contamination.
3. The influence of temperature: In general, the higher temperature, the better results.
4. Relative humidity: Relative humidity too high or too low will affect the disinfection effect. Relative humidity of 50-70% is best effect for chlorine dioxide sterilization.
5. PH (PH value): PH value will reduce or increase the activity of disinfectants. The chlorine dioxide effect is better in acidic environments.
6. Organic substances: Sterile environment of organic material can often inhibit or reduce disinfection and sterilization effect.
7. Antagonistic substances: For chemical disinfection, pay attention to antagonistic substances interference, such as acid or alkaline disinfectants would be reaction with alkaline or acidic material, reduced disinfection effect.
Selection Criteria for Disinfectant
1. Safe: Select non-toxic, no residue, no corrosion and no secondary pollution of the disinfectant.
2. Bacterial effect: Demand for quick and efficient, broad-spectrum disinfectant and low impact of environment.
3. Economic: Request use of low concentration and prices.
4. Operation: Used method is simple and convenient.