01 October 2025

The Effects of Ozone on Microorganisms - Germs, Bacteria, Viruses and Fungi

Ozone (O₃), thanks to its powerful oxidative properties, renders germs, bacteria and viruses inactive by disrupting their cell structures and proteins. This process occurs through oxidation, as ozone reacts with cell membranes, lipid structures and genetic material. The effect of ozone on these microorganisms can vary for each group. Below, we detail how ozone works on these three groups.

The Effect of Ozone on Bacteria

Bacteria are sensitive in structure to the oxidative effects of ozone. Ozone reacts with the lipids and proteins in the cell wall of bacteria, breaking down the cell membrane and damaging the internal structure of the cell. Although Gram-negative and Gram-positive bacteria have different levels of resistance, the oxidative effect of ozone destroys the cell wall of these bacteria and the bacterium is inactivated.
- Gram-negative bacteria (for example, Escherichia coli, Salmonella): Thanks to their thinner cell walls, it is easier for ozone to enter and oxidise these structures.
- Gram-positive bacteria (for example, Staphylococcus aureus): Despite having thicker cell walls, ozone also renders these bacteria inactive by breaking down their cell membranes.
The Effect of Ozone on Viruses

Viruses are microorganisms on which ozone is effective against their lipid envelopes and nucleic acids. Ozone inactivates both enveloped and non-enveloped viruses, but this effectiveness varies depending on the structure of the virus:
- Viruses with a lipid envelope (for example, Influenza, Coronavirus): Ozone oxidises the lipid envelopes of these viruses and causes deterioration in their protein structures. This process prevents the virus from binding to the host cell and replicating.
- Viruses without a lipid envelope (for example, Norovirus): In these viruses, ozone directly attacks the nucleic acids and causes the genetic material to deteriorate, thereby inactivating the virus.
The Effect of Ozone on Germs and Fungi

Ozone is also an effective disinfectant against germs and fungal spores. It particularly prevents the growth and reproduction of fungal spores, which have resistant cell walls. In order for ozone to be effective against this type of microorganism, higher concentrations and longer-duration applications may be required.

The Role of Ozone in Hygiene, Disinfection and Indoor Ventilation

Ozone (O₃), as a powerful oxidant found in nature, renders germs, bacteria and viruses inactive by disrupting their cell membranes and protein structure. This powerful oxidative effect prevents the growth and reproduction of microorganisms. In particular, while providing disinfection in enclosed spaces and on surfaces, it leaves no chemical residue after application. This makes ozone an environmentally friendly and reliable option compared to other disinfectants such as chlorine.

The application of ozone maximises its effectiveness through correct concentration and time management. Using ozone generators, ozone gas can be applied at certain ppm (parts per million) levels in the desired areas, and this process ensures the complete destruction of germs. However, each microorganism has a different level of resistance to the effects of ozone. For this reason, the correct setting of concentration and time is of critical importance.

Applications and Advantages of Ozone

Thanks to the effect of ozone on germs, bacteria and viruses, it is used for hygiene and disinfection purposes in many different fields:

Healthcare Institutions: In areas requiring high levels of sterilisation, such as operating theatres, patient rooms and laboratories, the application of ozone helps prevent hospital infections. Ozone quickly inactivates pathogens in the air and on surfaces in these areas, and shows high effectiveness even against antibiotic-resistant bacteria (for example, MRSA).
Food Processing Facilities: In food production and processing facilities, ozone is used to prevent microbial contamination on surfaces and equipment. Ozone extends the shelf life of food by destroying pathogens and fungal spores on food surfaces. It is also effective in removing pesticide residues. Applying ozone in vapour form makes it possible to provide disinfection without damaging the surfaces of food.
Water Treatment Systems: Ozone is widely used in drinking water and wastewater treatment. It is extremely effective in destroying bacteria, viruses and protozoa (for example, Giardia and Cryptosporidium) in water. When ozone is injected into water, it disrupts the cell structure of these microorganisms, achieving inactivation. It also prevents the formation of by-products of chemicals such as chlorine.
Indoor Ventilation and Enclosed-Space Disinfection: Ozone, used in ventilation systems or in enclosed spaces, contributes to the destruction of airborne pathogens (for example, fungal spores, viruses). In places with high human density, such as offices, hotels and schools, the application of ozone through ventilation systems prevents the spread of respiratory tract infections. The fact that ozone reverts to oxygen within a short time after application ensures that it leaves no harmful residue afterwards.

The Effect of Ozone on Microorganisms

The table below details the effects of ozone on different types of germs, bacteria and viruses, along with the required concentrations and application times. These values show that the effect of ozone can vary according to the type and structure of the microorganism:

Microorganism	Type	Ozone Concentration (ppm)	Application Time (Minutes)	Level of Effect (Kill Rate)
Escherichia coli	Bacterium	0.1 ppm	5 min	99.9%
Staphylococcus aureus	Bacterium	0.2 ppm	10 min	99.9%
Salmonella spp.	Bacterium	0.3 ppm	15 min	99.9%
Influenza Virus	Virus	0.05 ppm	5 min	99.99%
Coronavirus	Virus	0.1 ppm	10 min	99.99%
Norovirus	Virus	0.1 ppm	10 min	99.99%
Aspergillus niger	Fungus	0.4 ppm	20 min	99.9%
Clostridium difficile	Bacterial spore	0.5 ppm	30 min	99.9%
Hepatitis A Virus	Virus	0.15 ppm	15 min	99.9%
Candida albicans	Fungus	0.35 ppm	25 min	99.9%

Table Notes

Escherichia coli (E. coli): This bacterium, a common cause of foodborne illnesses, is destroyed rapidly even at low ozone concentrations.
Staphylococcus aureus: This bacterium, which can cause skin and respiratory tract infections, is rendered inactive by ozone breaking down its cell membranes.
Salmonella spp.: Salmonella, a significant risk for foodborne infections, can be safely inactivated on food surfaces using ozone.
Coronavirus, Norovirus and Influenza Virus: With the use of ozone in enclosed spaces and on surfaces, these viruses are rapidly rendered inactive and their spread is prevented.
Aspergillus niger: The application of ozone against fungal spores is effective in bringing the mould problem under control, especially in damp areas.
Clostridium difficile: This pathogen, one of the hardy spore-forming bacteria, is inactivated through long-duration ozone applications in healthcare facilities.
Hepatitis A: This virus, which causes foodborne and waterborne infections, is rendered inactive through ozone disrupting the genetic material, which is particularly important in terms of food safety.
Candida albicans: This microorganism, which can cause fungal infections, is rendered inactive thanks to the effect of ozone on its cell membrane and spores, thereby preventing fungus-related health problems.

Conclusion

Ozone, with its powerful oxidative effect, effectively inactivates bacteria, viruses and germs. With correct concentration and time management, it has a wide range of applications. At this point, as OCS OZON, with our experience and expertise in the sector, we aim to deliver the best results in hygiene and disinfection projects. Our company provides the reliability and expertise needed in the sector by offering ozone generator manufacturing, engineering design, maintenance and renovation services.

The correct management and engineering design of ozone applications increases the effectiveness and reliability of this powerful disinfectant. As OCS OZON, by offering tailored solutions with our expert team, we are proud to be a reliable partner for businesses in their hygiene and disinfection processes.