The general sterilization methods currently on the market mainly include ozone micro alcohol sterilization, ultraviolet irradiation sterilization, formaldehyde sterilization, and currently emerging hydrogen peroxide sterilization. The above sterilization methods are used on various occasions, but the traditional Bacterial methods have fatal shortcomings in practical applications.

To overcome the problems caused by traditional sterilization methods: poor sterilization effect, high corrosiveness to equipment, and great harm to the human body, etc., hydrogen peroxide space sterilization series equipment came into being.

Hydrogen Peroxide, A Potent Disinfectant

First of all, hydrogen peroxide (H2O2) is a naturally occurring chemical substance that exists widely in air and water. As early as the eighteenth century, humans discovered and started to use hydrogen peroxide, which is widely used in food, beverage, medical equipment, and health care. The use of hydrogen peroxide depends mainly on the degree of oxidation, and different concentrations of hydrogen peroxide have different uses.

The concentration of general medical hydrogen peroxide (commonly known as hydrogen peroxide) is 3%, which is mainly used to disinfect wounds or otitis media. In the case of wounds, pus, or dirt on the skin, mouth, and mucous membranes, it is immediately decomposed into oxygen. Oxygen does not combine with oxygen molecules and has a strong oxidizing ability. When it comes into contact with bacteria, it can destroy the bacteria and kill them. The substances remaining after killing the bacteria are water and oxygen without any toxicity or irritation. No secondary pollution and drug resistance will occur. Therefore, medical hydrogen peroxide is an ideal wound disinfectant.

The concentration of industrial hydrogen peroxide is generally 25-50%. High concentration hydrogen peroxide is highly corrosive and has an explosion hazard. If the concentration exceeds 8%, it needs to be packed and transported in a special container. When liquid hydrogen peroxide is used for disinfection, high-concentration and long-term contact are required to kill highly resistant microorganisms such as bacterial spores and fungi. For example, when the 7.5% hydrogen peroxide disinfectant produced by Reckitt Benckiser (approved by the FDA for advanced surface sterilization) is used to disinfect, the sterilization time at 20 ℃ is 6 hours.

Vaporized Hydrogen Peroxide

In order to give utilize maximum advantages of hydrogen peroxide disinfection and sterilization (no drug resistance and residue), and to overcome its shortcomings of high concentration corrosivity, low concentration, low efficiency, etc., researchers at home and abroad have studied it. In the 1980s, American researchers discovered for the first time that vaporized hydrogen peroxide has more than 200 times the sterilization ability of liquid hydrogen peroxide. In other words, hydrogen peroxide only needs a relatively low concentration in the gas phase to achieve the spore killing ability of high concentration liquid hydrogen peroxide. As a result, two different hydrogen peroxide gas disinfection and sterilization technologies have emerged:

• Vaporized Hydrogen Peroxide Sterilization Technology
• Hydrogen Peroxide "dry mist" Sterilization Technology

Vaporized Hydrogen Peroxide Sterilization

This type of sterilization mostly uses flash evaporation technique; dropping a high concentration of hydrogen peroxide solution (generally more than 30%) on the surface of heated and smooth metal objects, and instantaneously gasifying into 2-6-micron particles. The following table shows the technical advantages of VHP sterilization system:

Sterilization time Short sterilization time with minimum of 15 minutes
Sterilization Efficacy The disinfection effect reaches Log6 (ATCC12980 / 7953 Bacillus stearothermophilus)
Personnel safety VHP residue:1ppm Decomposes into water and oxygen (no effect on personnel health)
Equipment stability The system can meet the needs of high frequency use,and maintain trouble-free operation
Material Compatibility The dry mist hydrogen peroxide sterilization cycle is compatible with most materials, including all kinds of precision equipment, computers, room ceilings, and floors in the room. You can check the AAMI TIR17 technical standard

Dry-mist Hydrogen Peroxide Sterilization

In this type of hydrogen peroxide sterilization, a special device is used, which is a dry-mist hydrogen peroxide sterilization device. Since the Vaporized Hydrogen Peroxide Sterilization equipment developed by the flash evaporation technology requires a high concentration of hydrogen peroxide, it is highly corrosive and expensive. The scope of application is limited to the disinfection and sterilization of small anticorrosive enclosed spaces such as transfer cabins, isolators, freeze dryers, biological safety cabinets, medical equipment, biological incubators, and airlocks. It is not suitable for disinfection and sterilization of GMP clean workshops, hospital operating rooms, and other large spaces.

With the development of atomization technology, people have been able to atomize the disinfectant solution into small particles smaller than ten μm, so-called dry mist. Because these small particles move irregularly in the air (Brownian motion principle), they will not settle, nor will they aggregate to produce large droplets. They will rebound after contacting the surface of the object and will not decompose to make the surface wet. Therefore, these characteristics of dry mist make it very diffusible, leaving no dead corners during disinfection, no wet surface, no corrosion of equipment, color steel plates, and walls.

The results show that the smaller the atomized particles, the longer the suspension time in the air, and the greater the chance of full contact with bacteria in the air, to achieve the purpose of disinfection and sterilization. The following table compares the vaporized hydrogen peroxide sterilization system with traditional formaldehyde fumigation and ozone sterilization.

Project Dry-mist Hydrogen Peroxide Sterilization System Formaldehyde Fumigation Ozone
Residue Basically, zero residue on surface space White crystals need to be cleaned after the sterilization process, and the residue is difficult to completely remove The residue needs to be removed, and it is equally difficult to remove it completely
Chemical toxicity Hydrogen peroxide is non-toxic Carcinogenic EPA does not certify the strong oxidation and the harm of human respiratory system
Disinfection effect Log4-log6 broad-spectrum sterilization effect, such as spores, fungi, etc. Cannot fully achieve the log4-log6 spore killing effect At high concentration, it has spore killing effect, but due to the rapid cracking, it is difficult to achieve spore killing effect in a clean room
Overall sterilization time 2-6 hours At least 2 days Most users use the daily operation method, which is a potential hazard to the compatibility of the clean room environment.
Residual neutralization No need to neutralize Needs neutralization and cleaning
Certification Dry-mist hydrogen peroxide sterilization system passed EPA certification European and American advanced pharmaceutical and biotechnology companies have abandoned this sterilization method No EPA certification
Residue detection system Through the space residual detector, it can detect the residual amount of maintenance
Cost evaluation From the aspects of residue, chemical toxicity, sterilization effect, and certification in accordance with national GMP, national and international relevant standards, cost neutralization needs to be considered. Less turnout time, better employee protection, and simple operation all determine the cost-effectiveness of Dry-mist hydrogen peroxide sterilized

Hangzhou Metso Biological Technology Co., Ltd.

To meet the sterilization requirement in different environments, Hangzhou Metso Biological Technology Co., Ltd. has developed a number of different types of equipment, including vaporized hydrogen peroxide sterilization system and dry mist hydrogen peroxide sterilization system. The dry mist hydrogen peroxide sterilization system is divided into two categories: High-Pressure Fan type and Air Source type. Various types of hydrogen peroxide sterilization systems ensure the sterilization effect required in different environments. If you are interested in having your environment sterilized, please contact our company to provide you with the best solution.