Ultraviolet Sterilization

UV sterilization or ultraviolet germicidal irradiation destroys microorganisms by breaking their chemical bonds and scrambling their structure, rendering them unable to reproduce. It is one of the most effective disinfection methods.


Many commercial products use UV to sanitize surfaces. These include wands that you can wave over sketchy hotel sheets or your baby’s pacifier, though they don’t replace proven infection control measures like mask-wearing and social distancing.

Water Treatment

The UV light destroys the genetic material of disease-causing organisms within wastewater effluent and prevents them from multiplying. It has gained popularity as an alternative to chlorination for disinfection of water in onsite wastewater systems, especially after water treatment with reverse osmosis, water softening or filtration. The system must be carefully designed and located to ensure that the pathogenic organisms are not shielded from the UV light. Turbidity, suspended solids, and the flow rate of the wastewater must also be carefully controlled to allow proper contact time.

UV irradiation is very effective against bacteria and viruses, but not as effective against other microorganisms that have outer coatings or form cyst states (such as Giardia). The cellular damage caused by the UV radiation creates pyrimidine dimers within the DNA molecule, which prevents the cell from replicating, and thus, it cannot spread infectiousness.

The process does not change the taste, color or odor of the treated water, and it requires no chemical input. It is also quick, does not produce residuals and does not require specialized storage conditions. It is commonly used to disinfect water bottles and equipment in food processing facilities. It is also used in pharmaceutical production to sterilize water and solvents, and in microbiology laboratories to disinfect work surfaces and instruments between uses. It is also being used by juice producers to sterilize the contents of PET bottles and is being evaluated for use in the onsite sterilization of fruit and vegetable juices.

Food Processing

The food and beverage industry uses UV-C sterilization to protect their products. The FDA has ruled that it’s an acceptable alternative to cold pasteurization for many liquid foods. The process is often used to sterilize juices, ciders and egg products (but not milk).

The effectiveness of UV sterilization in liquid foods depends on several factors. One of the most important is the sensitivity of the microorganism being treated to UV radiation. This sensitivity is usually determined by the presence or absence of UV absorbing proteins in the cell wall, or by the structure of the nucleic acids themselves.

Another factor is the time required for a specific log-reduction of the target microorganism in the UV irradiation. This is determined by performing a biodosimetry test that involves passing a challenge microorganism through a full-scale UV reactor and measuring the reduction of the population. The data is then converted to a dose or reduction equivalent fluence, also known as germicidal fluence, based on the known UV sensitivity of that particular pathogen from lab scale CB tests.

Other factors that need to be addressed include determining the impact of UV on vitamins and other natural antioxidants in liquid foods. The spectral response of these compounds needs to be understood to optimize microbial inactivation and minimize vitamin losses. Lastly, the physical properties of the food product to be treated need to be considered to determine the best way to use a UV reactor for liquid foods processing, including fluid momentum transfer and flow patterns, optical properties, water activity and chemical composition.


As viruses and bacteria become increasingly resistant to chemical disinfectants, hospitals are turning to UV light for sterilization of rooms, surfaces and air. The UVC radiation emitted by germicidal lamps penetrates the cells of microorganisms, destroying them and making them unable to reproduce or infect patients. This type of sterilization is a great alternative to chemical disinfectants that are often ineffective and can cause negative side effects.

Studies show that using UV-C on patient room surfaces results in a significant reduction of pathogens compared to traditional surface cleaning and disinfection. This can reduce healthcare-associated infections, or HAIs, which account for more than a quarter of all infections acquired in hospital settings and cost billions to treat annually.

Using UV-C also helps prevent the spread of multi-drug resistant organisms (MROs) between patients. These infections can be especially deadly for infants and elderly patients. UV-C has also been shown to be effective at killing the water-borne parasite Cryptosporidium, which causes intestinal infections in humans and animals.

With a diverse population of patients, many of whom may have different immune systems, hospitals are recognizing the need for safer and more efficient disinfection methods. The use of UV-C in a hospital setting can dramatically improve the quality of care and increase patient safety. Using wall mounted units in restrooms, or even mobile UVC robots that can be rolled from room to room, can significantly cut down the time needed for manual cleaning and disinfection of hospital surfaces and equipment.


UVC radiation ionizes molecules and causes them to break apart or to form new chemical bonds. This process kills microorganisms and disinfects materials.

The ionization effect of UVC light is why it works so well in sterilizing products. The ionization of DNA molecules inside bacteria and viruses prevents them from reproducing. It also stops their reproduction by preventing a key chemical reaction that is necessary for cell growth.

This makes it possible to sterilize bacteria and viruses without using chemicals, which means that no harmful residues are left behind. This makes UVC sterilization a very green technology.

There is a lot of buzz about the use of UVC light for sterilizing products and surfaces. Many people are worried about the potential health risks of using this technology. There are some concerns about skin cancer.

Fortunately, these concerns are overstated. Most UVC rays are absorbed by oxygen high in the atmosphere and do not reach the ground. The UVC rays that do reach the ground come from man-made sources such as tanning booths, black lights for fluorescent paint and dye, curing lamps for coatings, mercury and arc welding torches, and UV sanitizing bulbs.

People need to follow the safety instructions included with UV wands and to wear protective eyewear when working with these devices. UVC light can be dangerous to humans, but it is usually used in areas that are not open to the public.