Recently, a UVC disinfection bag with the size of a makeup bag, only 3 minutes, you can use the child’s bottles, clothing, toys and even masks to disinfect, to extend the use of masks time, and claims that the bacteria kill rate of up to 99.9%, is this true? Is this black technology reliable? Let’s uncover the mystery of this “sterilizer” together.

UVC Disinfection Bag

According to the “Pneumonia Treatment Protocol for COVID-19 Infection (Trial Version 7)“, the COVID-19 virus is sensitive to ultraviolet light and heat. Since the outbreak, all kinds of net products for disinfection and health needs have sprung up.

UVC disinfection bag, is one of them. The average price of such products ranges from two hundred to one thousand dollars, and according to the e-commerce platform web page claims that “as long as you can put it can be disinfected”. Whether it’s a bottle pacifier and other baby products, or women’s intimate apparel, cell phones, keys, or even masks worn on the go, you can put it in the sterilization kit to disinfect.

The construction of this type of products are similar, mainly including the container, UV generator, control circuit. The container mainly contains items and prevents UV leakage, and its interior has light-reflecting materials to ensure that the items inside can be irradiated by UV light.

UV generators produce UV light, generally divided into two kinds of LED and UV lamps. UV lamps are effective against coronaviruses but produce ozone. UV lamps are harmful to the skin and are non-visible, so blue light is added to the items to alert consumers. The control circuit can control the disinfection time and open cover detection.

These products have emerged in the early years, when they were mainly used to disinfect products such as milk bottles, but they did not catch on due to low product awareness and other reasons. After this COVID-19 outbreak, the demand for such disinfection products increased, while their advantages of short disinfection time and portable operation make them suitable for modern fast-paced life.

Can UVC disinfection bag sterilizer? Bacteria killing rate is greater than 99.99%

According to the e-commerce platform’s webpage, the UV disinfection kit has a bacterial kill rate of 99.9%. SGS Agri-Food Laboratories senior technical engineer Qiu Yan tested the product for bactericidal effectiveness to verify the efficacy of the disinfection kit. She selected Escherichia coli and Staphylococcus aureus as the bacterial samples, which are representatives of Gram-negative and positive bacteria, respectively, both common foodborne pathogenic microorganisms.

UV disinfection kit

UV disinfection kit

The engineers tested the sterilization effectiveness of the disinfection kit: this experiment set up a control group and an experimental group, and the bacterial killing rate was derived by comparing the results. Slides with certain concentrations of E. coli and S. aureus were put into the disinfection kit, and after the operation of the kit, the slides were removed and counted after 48 hours of constant temperature incubation by elution, dilution and pouring into the culture medium.

UV disinfection kit

Left: unsterilized reference group  Right: experimental group disinfected by sterilization kit

UVC Disinfection Bag

Experimental results show that the UV disinfection package for the two bacteria are greater than 3.00 log kill value (kill rate greater than 99.99%), indicating that it is possible to achieve a certain sterilization effect.

It is reported that ultraviolet light is the sunlight wavelength 100 ~ 400 nanometers of light, divided into UVA, UVB, UVC, UVD, the real germicidal effect is UVC ultraviolet. The sterilization principle is through the irradiation of ultraviolet light, damage and change the molecular structure of microbial DNA (deoxyribonucleic acid) or RNA (ribonucleic acid), resulting in the death of growth cells and (or) regenerative cell death, to achieve the effect of sterilization.

Are there any safety hazards when disinfecting the product? Illumination leakage value is within the safe range

UVC sterilization, there are also safety hazards. Ye Hanxiang introduced, due to the destructive effect of ultraviolet light on biological cells, in the use of ultraviolet germicidal lamps should be careful not to directly irradiate the human skin, and not directly with the eyes to look directly at the lamp.

UVC Disinfection Bag2

“A special reminder is that ultraviolet light is non-visible light. That is, it is invisible to the naked eye, and all we can see is the visible light component of the disinfection lamp. When we feel the burn, the human body has already suffered serious injury.”

The reporter found that because some disinfection kits come with see-through windows, the disinfection lamp can be seen at any time; some samples of disinfection kits have blue light leaking out when the zipper is not in place or the lid is not closed, obviously. Will these ultraviolet rays cause harm to the human body?

In the photobiological safety laboratory, engineers conducted safety tests on the leaked light. The experimental results show that the UV intensity of the two samples belongs to the “non-hazardous category”, that is, the light leakage value is within the safe range. And the UV wavelength is concentrated in 253 nanometers. The study found that sufficient intensity of 253 nm wavelength UV light, irradiation 30 seconds ~ 1 minute can kill the COVID-19.

The test found that the light leakage value of the disinfection kit was within the safe range and the wavelength was effective in killing the coronavirus.

Disinfection kit will not leak electricity? Ye Hanxiang said, “like the plug-in disinfection box 220V power supply has the risk of leakage, for this reason the inner wall of these products to increase the metal shell to prevent ultraviolet radiation plastic parts, to avoid causing the shell plastic aging produces leakage risk. And disinfection package 5V power supply low voltage, leakage causes less impact, it is not necessary to use the metal inner shell protection.”

UVC Disinfection Bag

5V power supply low voltage sterilization package is not protected by metal inner case

5V power supply low voltage sterilization package is not protected by metal inner case

What is the sterilization principle of the UVC disinfection bag? General disinfection through ultraviolet light?

During the epidemic to meet public demand, all kinds of new disinfection products have come on the market, so that people dazzled. It is reported that the sterilization principle of common home appliance sterilization products on the market include three main types: high-temperature disinfection, ultraviolet disinfection, negative ion/ozone disinfection. These disinfection principles have their own advantages and disadvantages, applicable objects and scenarios are also different.

Bottle sterilizers, radiation sterilization cupboards and other basic high-temperature steam sterilization method, with high temperatures of more than 100 ℃ to inactivate bacteria, is a reliable way to sterilize. However, it must be done in a sealed environment, and it may damage the waterproof layer of the product, and the temperature is too high to easily damage the product or cause scalding accidents.

The common disinfection package on the market is generally sterilized by ultraviolet light. The advantage is the use of UVC band sterilization effect is the best, and does not require an enclosed space, to ensure that the irradiation can be. The disadvantage is the low penetration, stacked objects disinfection effect is poor, and direct irradiation of skin and eye damage, protection is not in place, harm to the human body is not felt, long-term irradiation will lead to plastic aging.

Ozone/negative ion disinfection is the air discharge generated by the electrons captured by oxygen atoms O2, producing negative air ions O3, or ozone. The advantages are obvious, the gas is easy to diffuse, low power consumption, and the generator is small in size. The disadvantages are that the gas tends to leak, injure or even irritate the respiratory tract and cause dizziness. Typical products include air purifiers.

Which products cannot be sterilized by the disinfection package? Sun umbrellas are not recommended to be put into the UVC disinfection bag

According to the disinfection principle of the disinfection kit, what are the points of attention in the selection of materials for disinfection objects? Ye Hanxiang introduced, plastic, silicone sensitive to ultraviolet light, long-term exposure to easy aging, hardening, so this type of material products are not recommended for long-term use disinfection kit, high-temperature disinfection is a better way to disinfect.

“Some UV protection items such as sun umbrellas, UV light is difficult to penetrate, also not suitable for disinfection with UV. There are also stacked up clothes, disinfection of such products need to ensure that the contaminated surface are able to irradiate UV light, stacked fabric in fact, only the surface of the clothes have a good disinfection effect.”

The longer the exposure time within the product, the better the disinfection effect

In the use of maintenance, some disinfection package business web page claims that “removable, washable”. So will washing affect the use of the effect? Ye Hanxiang said, in terms of safety, it is not recommended that the design. Because the disassembled part if not installed, it is easy to cause UV leakage. So the design should pay attention to the fact that the product can not work until it is installed.

What are other considerations for the daily use of disinfection kits? Ye Hanxiang introduced the need to note that all disinfection kits have a disinfection time, do not interrupt the disinfection process before it is completed. “For example, open the disinfection kit during disinfection and add disinfection items so that the whole disinfection process needs to be done again. Within the range of irradiation time set by the product, the disinfection effect is related to the time, the longer the light time the better the effect, but be careful not to expose plastic, silicone and other products to UV light for a long time.”

“The product that meets this requirement, the package itself can be washed after the part with the electrical connection is disassembled. But pay attention to the disinfection package after washing, must be dry before installation and use. The installation must be in place to avoid leaks.”

What else should I pay attention to when using the disinfection kit? Use with a well-ventilated environment

Disinfection kits use ultraviolet light and ozone to kill viruses, which is a physical disinfection method. They are mainly used for disinfection of surfaces, usually not too far away, and the intensity needs to meet the requirements, and people and pets need to stay away when using them to avoid damage to human eyes and skin. At the same time some UV disinfectors will produce ozone, must pay attention to the use of good ventilation environment.

The disinfectants commonly used by the general public are chemically based, using organic solvents to denature proteins and destroy the structure of pathogens directly, or using the strong oxidizing properties of biocides to kill indiscriminately. According to SGS cosmetics and daily chemical products laboratory technical manager Li Jichao, there is also a fogging disinfector on the market, which is the use of ultrasonic atomizer, the disinfectant atomized and sprayed into the disinfection space, the advantage of these products is a large spray range, short operating time, but its only a way to use, the focus should be on what specific disinfectants are used.

“Common active ingredients include chlorine-containing disinfectants, alcohol disinfectants, and quaternary ammonium disinfectants. Some disinfectants, such as peroxide-based disinfectants and chlorine dioxide disinfectants, are not exposed to much in the daily lives of residents because the former undergoes chemical changes in its placement and the latter is inherently dangerous.”