Scientists have determined that salmon post-smolts tolerate similar levels of ozone in brackish water – which is increasingly used in RAS facilities – as they do in freshwater.
Ozone is a strong oxidant, commonly used for improving water quality and disinfecting pathogens in freshwater fish farms. When ozone reacts with certain constituents of seawater, however, toxic byproducts can severely impact the health of fish populations. As brackish water is increasingly introduced in farming post-smolt salmon, thresholds for the safe use of ozone need to be established. Suppliers of recirculating aquaculture systems (RAS) are looking for safe, cost-efficient and reliable ways to maintain optimal water quality in brackish water RAS, and with this research they are now a step closer.
Scientists from Nofima and The Conservation Fund Freshwater Institute (TCFFI), both central in CtrlAQUA (Centre for research-based innovation), wanted to determine if ozone is safe for salmon in brackish water, and what the safe limits are for post-smolts.
The scientists carried out a trial determining the ozone limit in a flow-through system. Atlantic salmon at 100 grams were reared in brackish water of 12 ppt (parts per thousand) salinity for 12 days. They were exposed to ozone levels of 250 (control), 280 (low), 350 (medium), 425 (high) and 500 (very high) mV (millivolts). They identified ozone levels up to 350mV as potentially safe and 300 mV as safe for the health of post-smolts in flow-through brackish water.
In a follow-up study by Nofima that is not yet published, the identified threshold was confirmed for RAS. Carlo Lazado, fish health researcher in Nofima, will present the results at the digital conference “Smolt production in the future”, on 21 October.
Chris Good, scientist at TCFFI, reports that even lower ozone dosages are sufficient to improve water quality.
“This would depend on the quality of water being treated but in our experience in replicated freshwater RAS, a lower ozone level of 290 mV still resulted in significant improvements to water quality in general, including reduced biochemical oxygen demand and increased UV transmittance,” Good says.
Here is a great open article on the use of ozone in aquaculture.
The most common topic for discussion around workplace water cools is not bacteria. However, there is a certain strain of bacteria that has generated a good amount of press and discussion. The strain of bacteria, E. coli O157:H7 has become popular in the media which cause many people to have a healthy fear of this bacteria.
Escherichia coli (E. coli) is a strain of bacteria that is commonly found in the intestines of animals and humans, and are known to be dangerous and can cause food borne illnesses. The strain of bacteria, E. coli O157:H7 can be life threatening and has resulted in an estimated 2,100 hospitalizations, and is one of the most dangerous strains of E. coli.
Many vegetables, meats and even water supply can contain this strain of E. coli. The biggest cause of infections from E. coli are from food borne illnesses like under cooked ground beef. However, some waterborne illnesses have been found as well. The Canadian town of Walkerton, Ontario had a municipal water supply contaminated by this strain of E. coli in May of 2000. As a result, the pathogen has been blamed for over 2,000 illnesses and 7 deaths.
Solutions to reduce food borne pathogens are becoming very rare. For example, in the past, chlorine has been widely used as a cheap and effective oxidizer to kill a variety of pathogens. However, chlorine is being used less and less as the side effects of the chemical are slowly becoming more apparent. Other chemicals such as methyl bromide, chlorine dioxide, and sodium hypochlorite, that have been used to combat pathogens in the past are also being used less because of the awareness of side-effects.
Ozone is found to be a new, and effective method of antimicrobial intervention. In certain industries such as drinking water, food processing, and surface sanitation, ozone is becoming very popular. Ozone has been proven to be an effective disinfectant against many different pathogens, but studies needed to be conducted in order to prove it was useful against this particular strain of E. coli O157:H7. After research was conducted, it was proven that ozone is effective against this strain of E. coli.
Below is an excerpt from the Direct food additive Petition presented to the FDA in August 2000 to achieve GRAS status for the use of ozone to inactivate E. coli O157:H7, along with other pathogens.
Using this data, a determination of spray nozzles, spray bars, or even conveyers can be established. It is clearly shown that 2.0 ppm of aqueous ozone is very effective in only a short period of time, while higher ozone levels show only marginal improvement.
Ozone can be used in drinking water to inactivate E. coli O157:H7. This has been confirmed by the EPA and recognized as a suitable disinfectant for water.
The use of gaseous ozone for the elimination of pathogens is less common. There is also less research showing the effects of gaseous ozone on bacteria. The application of gaseous ozone is dependent upon the temperature, humidity, contact time, and ozone levels. Research has been conducted to determine that gaseous ozone will reduce and inactivate E. coli O157:H7, however more research is necessary to determine the effectiveness of ozone within different variables.
Papers on the use of ozone to eliminate E.coli O157:H7
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Paper number 056147, 2005 ASAE Annual Meeting . @2005 Authors: Katherine L. Bialka, Ali Demirci Keywords: E. coli O157:H7, Salmonella, strawberry, gaseous ozone
Each year there are approximately 76 million foodborne illnesses and fresh produce is the second most common vehicle for such illnesses. Small fruits have been implicated in several outbreaks although none have been bacterial. Prior to market small fruits are not washed or treated in any manner so as to extend their shelf life. Washing alone is not a viable option and the use of novel technologies needs to be investigated. One such technology is ozone which has been used to treat drinking water since the late nineteenth century. The efficacy of gaseous ozone to decontaminate pathogens on strawberries, which were used as a model for small fruits, was investigated in this study. Strawberries were artificially contaminated with 5 strains of E. coli O157:H7 and Salmonella. Fruits were treated with 4 ozone treatments; i) continuous ozone flow for 2, 4, 8, 16, 32, and 64 min, ii) pressurized ozone (83 kPa) for 2, 4, 8, 16, 32, and 64 min, iii) continuous ozone (64 min) followed by pressurized ozone (64 min). Maximum reductions of 1.81, 2.32, and 2.96 log10 CFU/g of E. coli O157:H7 were achieved for continuous, pressurized, and continuous followed by pressurized ozone, respectively. For Salmonella reductions of 0.97, 2.18, and 2.60 log10 CFU/g were achieved for continuous, pressurized, and continuous followed by pressurized ozone, respectively. It was concluded that continuous ozone was the least effective treatment, and that there was no significant difference between pressurized ozone treatment and continuous followed by pressurized ozone treatment. These results demonstrate that gaseous ozone has the potential to be used a decontamination method for small fruits.
Effectiveness of ozone for inactivation of Escherichia coli and Bacillus cereus in pistachios
Authors: Meltem Yesilcimen Akbas 1 & Murat Ozdemir 2*
1Department of Biology, Gebze Institute of Technology, PO Box 141, 41400 Gebze, Kocaeli, Turkey 2 Department of Chemical Engineering, Section of Food Technology, Gebze Institute of Technology, PO Box 141, 41400 Gebze, Kocaeli, Turkey
Copyright 2005 Institute of Food Science and Technology Trust Fund
The effectiveness of ozone for the decontamination of Escherichia coli and Bacillus cereus in kernels, shelled and ground pistachios was investigated. Pistachios were inoculated with known concentrations of E. coli and B. cereus. Pistachio samples were exposed to gaseous ozone in a chamber at three different concentrations (0.1, 0.5 and 1.0 ppm) for various times (0–360 min) at 20 °C and 70% relative humidity. The effectiveness of ozone against E. coli and B. cereus increased with increasing exposure time and ozone concentration. The physico-chemical properties including: pH, free fatty acids and peroxide values, colour and fatty acid composition of pistachios did not change significantly after the ozonation treatments, except for the peroxide value of ground pistachios ozonized at 1.0 ppm for 360 min. Ozone concentration of 1.0 ppm was effective in reducing E. coli and B. cereus counts in kernels and shelled pistachios, while ozone concentrations <1.0 ppm were found to be appropriate in reducing the number of both bacteria in ground pistachios without having any change in their physico-chemical properties.
Application of Ozone for Inactivation of Escherichia Coli O157:H7 on Inoculated Alfalfa Sprouts
Journal Of Food Processing And Preservation Research, 27 (2003) 51-64
Authors: Sharma, Demirci, Beuhat, Fett
Alfalfa sprouts contaminated with the bacterial pathogens Salmonella and Escherichia coli O157:H7 have been the source of several foodborne outbreaks in the US and other countries. New, more effective antibacterial treatments are required to ensure the microbial safety of sprouts for the consuming public. In this study, we tested the ability of ozone in water to eliminate E. coli O157:H7 from inoculated alfalfa sprouts. Treatments (from 2 to 64 minutes in durations) with ozone in water (up to 21 ppm) were tested. In some experiments the ozone was continuously fed into the water solution during treatment with or without pressurization. Immersion of sprouts into ozone in water reduced bacterial populations by less than 90%. With continuous feeding of ozone, reductions increased to 99%. The use of pressure during ozone treatments did not increase efficacy. The use of ozone alone will not ensure the microbial safety of sprouts, but ozone in combination with other antibacterial treatments may be able to achieve that goal.
Chemical treatments to eliminate pathogens on inoculated sprouts have shown little success. This study investigated the antimicrobial potential of ozone on alfalfa sprouts. Alfalfa sprouts inoculated with a five strain cocktail of Escherichia coli O157:H7 were immersed in water containing 21 ppm ozone for 2, 4, 8, 16, 32, 64 min at 4 C. To increase accessibility of ozone into sprout crevices alternative treatments with continuous ozone sparging with and without pressurization were evaluated. Immersion of inoculated alfalfa sprouts in water containing 21-ppm ozone reduced the population of E. coli O157:H7 by 85.8% at 64 min. There was no significant difference (P > 0.05) between treatment and control and also between different time intervals. Continuous ozone sparging resulted in 85.0 to 99.4% reduction, which was significantly higher (P 0.05) than reduction by sparging with air. Application of low hydrostatic pressure of 12 psi for 5 min subsequent to continuous ozone sparging for 2 – 64 min reduced E. coli O157:H7 populations by 99.0%. Pressurized ozone treatments did not differ significantly from un-pressurized ozone treatments except at 32 min. Ozone treatment did not have any visible detrimental effect on sprouts quality. Further investigation is required to develop methods for ozone introduction for decontaminating sprouts to reduce health risk. However ozone has the potential to replace chemical treatments being used
Efficacy of Ozone Against Escherichia coli O157:H7 on Apples
Authors: M. Achen and 1 A.E. Yousef 1
Authors are with the Department of Food Science and Technology, The Ohio State University, Parker Hall, 2015Fyffe Rd., Columbus, Ohio 43210. Direct inquiries to author Yousef (E-mail: email@example.com).
This research was supported by a grant from the Ohio Agricultural Research and Development Center. The authors to thank J.G. Kim for his valuable advice and technical support.
Copyright 2001 by the Institute of Food Technologists
Apples were inoculated with Escherichia coli O157:H7 and treated with ozone. Sanitization treatments were more effective when ozone was bubbled during apple washing than by dipping apples in pre-ozonated water. The corresponding decreases in counts of E. coli O157:H7 during 3-min treatments were 3.7 and 2.6 log10 CFU on apple surface, respectively, compared to < 1 log10 CFU decrease in the stem-calyx region in both delivery methods. Optimum conditions for decontamination of whole apples with ozone included a pretreatment with a wetting agent, followed by bubbling ozone for 3 min in the wash water, which decreased the count of E. coli O157:H7 by 3.3 log10CFU/g.
The efficacy of ozone as a water additive for washing raspberries and strawberries was investigated. Pathogen-inoculated fruits were treated with aqueous ozone concentrations of 1.7 to 8.9 mg/liter at 20 degrees C for 2 to 64 min, with an aqueous ozone concentration of 21 mg/liter at 4 degrees C for 64 min, or with water as a control. Maximum pathogen reductions on raspberries were 5.6 and 4.5 log CFU/g for Escherichia coli O157:H7 and Salmonella, respectively, at 4 degrees C, whereas reductions on strawberries were 2.9 and 3.3 log CFU/g for E. coli O157:H7 and Salmonella, respectively, at 20 degrees C after 64 min. Washing with water (sparging with air as control) resulted in reductions of approximately 1 log CFU/g. The results presented here indicate that aqueous ozone may be useful as a decontaminant for small fruits.
Inactivation of E. coli O157:H7 in apple cider by ozone at various temperatures and concentrations
Authors: STEENSTRUP Lotte Dock; FLOROS John D.
Authors Affiliations:BioCentrum-DTU, Technical University of Denmark, Søltofts Plods Bldg. 221, 2800 Lyngby, DANEMARK Department of Food Science, 111 Borland Laboratory, Penn State University, University Park, PA 16802, ETATS-UNIS
The effect of temperature (5-20C) at 860 ppm (v/v) ozone and different gaseous ozone concentrations above 1,000 ppm on inactivation of E. coli O157:H7 in apple cider was studied. Lag times ranged from 3.5 min at 20C to 6.7 min at 10C before the on-set of E. coli O157:H7 inactivation. D-values ranged from 0.6 to 1.5 min at 20C and 5C, respectively. After ozone treatment of cider for 14 min, dissipation of ozone from cider was slow, decreasing to about 5 mg/L after 2 h at 5C. At high gaseous ozone concentration, lag time was shortest and D-value lowest. There was a critical concentration of dissolved ozone of about 5-6 mg/L at 20C, before the on-set of E. coli O157:H7 inactivation in the cider. Total processing times, based on lag time plus 5D, ranged from about 4 to 14 min depending on temperature and ozone concentration. Overall, inactivation of E. coli O157:H7 by ozone was fast enough to allow practical applications in cider production, and it should be considered as an alternative to thermal pasteurization.
Journal Title: Journal of food processing and preservation ISSN 0145-8892 CODEN JFPPDL
The aim of this study was to integrate an ozone-based sanitization step into existing processing practices for fresh produce and to evaluate the efficacy of this step against Escherichia coli O157:H7. Baby spinach inoculated with E. coli O157:H7 (∼107 CFU/g) was treated in a pilot-scale system with combinations of vacuum cooling and sanitizing levels of ozone gas (SanVac). The contribution of process variables (ozone concentration, pressure, and treatment time) to lethality was investigated using response-surface methodology. SanVac processes decreased E. coli O157:H7 populations by up to 2.4 log CFU/g. An optimized SanVac process that inactivated 1.8 log CFU/g with no apparent damage to the quality of the spinach had the following parameters: O3 at 1.5 g/kg gas-mix (935 ppm, vol/vol), 10 psig of holding pressure, and 30 min of holding time. In a separate set of experiments, refrigerated spinach was treated with low ozone levels (8 to 16 mg/kg; 5 to 10 ppm, vol/vol) for up to 3 days in a system that simulated sanitization during transportation (SanTrans). The treatment decreased E. coli populations by up to 1.4 log CFU/g, and the optimum process resulted in a 1.0-log inactivation with minimal effect on product quality. In a third group of experiments, freshly harvested unprocessed spinach was inoculated with E. coli O157:H7 and sequentially subjected to optimized SanVac and SanTrans processes. This double treatment inactivated 4.1 to ≥5.0 log CFU/g, depending on the treatment time. These novel sanitization approaches were effective in considerably reducing the E. coli O157:H7 populations on spinach and should be relatively easy to integrate into existing fresh produce processes and practices.
Decontamination of Escherichia coli O157:H7 and Salmonella enterica on blueberries using ozone and pulsed UV-light.
Authors: K L Bialka; A Demirci
Publication Detail: Type: Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov’t; Research Support, U.S. Gov’t, Non-P.H.S.
Title: Journal of food science Volume: 72 ISSN: 1750-3841 ISO Abbreviation: J. Food Sci. Publication Date: 2007 Nov
Created Date: 2007-11-23 Completed Date: 2008-03-24
Efficacy of gaseous ozone, aqueous ozone, and pulsed UV-light was evaluated for the purpose of decontaminating blueberries artificially contaminated with either Escherichia coli O157:H7 or Salmonella. Blueberries were exposed to 4 different gaseous ozone treatments: continuous ozone exposure, pressurized ozone exposure, and 2 combined treatments. Maximum reductions of Salmonella and E. coli O157:H7 after 64-min pressurized or 64-min continuous exposure were 3.0 and 2.2 log(10) CFU/g, respectively. Aqueous ozone experiments were conducted at 20 degrees C and 4 degrees C and zero plate counts were observed for E. coli O157:H7 and Salmonella after 64 min of ozone exposure at 20 degrees C. Finally, pulsed UV-light was evaluated at 3 different distances from the light. Maximum reductions of 4.3 and 2.9 log(10) CFU/g were observed at 8 cm from the light after 60 s of treatment for Salmonella and E. coli O157:H7, respectively. A sensory analysis as well as color analysis was performed on blueberries from each treatment agent; neither analysis detected a difference between treated and untreated blueberries. The results presented in this study indicate that ozone and pulsed UV-light are good candidates for decontamination of blueberries.
Ozone has many applications and uses. Each are unique with its own specific nuances. The IOA offers a great deal of information and technical papers on these applications. Oxidation Technologies has the experience to provide you an engineered solution for many of these applications. See link below for details on some of the applications we can help with:
By the time this issue reaches our readers, we are hopeful that the numbers of new COVID-19 cases are starting to decrease, and the world is on the way to some form of recovery. Unfortunately, the recovery may take quite some time and there is always the concern of another wave.
Researchers are dedicating countless hours on ways to control the virus and protect the public against it. In the last issue of Ozone: Science & Engineering (OS&E), we presented a statement encouraging research into ozone inactivation of coronavirus. Ozone is known as being highly effective for the inactivation of many viruses.
We also referenced a paper published in OS&E in 2009 “Development of a Practical Method for Using Ozone Gas as a Virus Decontaminating Agent” by James B. Hudson and coauthors. The purpose of this work was to develop a practical method of utilizing ozone in a mobile apparatus that could be used to decontaminate rooms in health care facilities, hotels, and other buildings. The results showed that an ozone concentration of 20–25 ppm with > 90% relative humidity could provide at least 3 log inactivation on different hard and porous surfaces, and in the presence of biological fluids. One of the viruses successfully inactivated was the murine coronavirus used as a surrogate for the SARS virus. This paper is available open access and can be accessed at: https://doi.org/10.1080/01919510902747969. It has received more than 33,000 views as of this writing.
A free E-book is available for download from IWA publishing. This book is available as a PDF for free download. A great resource on the use of ozone in water and wastewater treatment. Should you have any interest in the use of ozone in wastewater treatment, download this book and keep it as s reference for future uses.
Nara Medical University (Professor Toshikazu Yano, Director of Infectious Diseases, Takashi Kasahara, Director of Infectious Diseases) and MBT Consortium (members of the Subcommittee on Infectious Diseases: Quorl Holdings Co., Ltd., Sanyu Shoji Co., Ltd., Tamuratec Co., Ltd., Marusan Pharmaceutical Biotech Co., Ltd.)
The company’s research team was the first in the world to confirm the inactivation of the new coronavirus by exposure to ozone gas.
“We also demonstrated academic practicality by experimentally clarifying the inactivation conditions”
The need to sterilize environments and equipment as a consequence of COVID-19 involves a lot of effort and time for manual cleaning.
One of the tools available to solve this problem was sterilization with ozone gas, but without clear scientific evidence, it was not possible to certify its use.
A research team led by Nara Medical University has been able to inactivate new coronaviruses through exposure to ozone gas.
In this report, we report that ozone inactivation of the new coronavirus has been conducted and the relationship between ozone concentration and exposure time and ozone inactivation has been clarified experimentally.
Ozone (chemical formula: O3) is an allotropic form of oxygen, with a characteristic garlic-like odor. Its molecules are made up of three oxygen atoms.
It has the strongest oxidative power close to fluoride and destroys cells like bacteria and decomposes the chemical bonds between substances.
It is effective in deodorization, sterilization and cleaning and is used in various fields such as medical care, nursing care, breeding and in the food sector.
As for the effectiveness of ozone, the bactericidal power of 7 times that of chlorine and has been considered “particularly effective” for the control of infectious diseases.
In Japan, the fire department of the Ministry of Internal Affairs and Communications introduced it to Japan for the first time in 2008, when it identified it as part of the measures to prevent the new flu infection and authorized its use in main airports.
Since then, application on medical sites has progressed and the number of medical institutions introducing ozone generators for the purpose of preventing the spread of healthcare associated infections has been increasing.
The bactericidal ozone-based approach has also been accepted as a measure against new coronavirus infection (COVID-19).
Since January of this year, when COVID-19 infection was spreading around the world, not only medical institutions, but also ambulances, hospitals, hotels, etc. have adopted ozone generators.
Ozone has definitely gained widespread use as an effective sterilization method comparable to manual alcohol cleaning.
Experiment content and procedure
Cultivate a new cell line of coronavirus,
place a stainless steel plate in an ozone-proof hermetic box installed in a safety cabinet,
apply the new coronavirus to be tested.
Use an ozonator (medical device certified by PMDA: ozone generator) installed in the ozone-proof hermetic box, the ozone concentration in the ozone-proof hermetic box is controlled and maintained from 1.0 to 6.0 ppm. The amount of ozone exposure is set by the CT value. (The CT 330 value is used, which is a verification test value for the certification of medical devices by the PMDA of the Ministry of Health, Labor and Wellness).
After exposure, inoculate the cells with the virus,
determine if the virus has infected the cells and calculate the amount of virus.
This experiment was possible because the University has a biosecurity level 3 laboratory and virus culture technology.
With a CT value of 330 (55 minute exposure to an ozone concentration of 6 ppm), it was inactivated from 1 / 1,000 to 1 / 10,000.
At a CT value of 60 (60 minutes of exposure to an ozone concentration of 1 ppm), it was inactivated from 1/10 to 1/100.
In this study, we confirmed that ozone can inactivate up to 1 / 10,000.
This shows that in real conditions and using ozone, the new coronavirus can be inactivated on all surfaces and used in the sanitization of environments.
But ozone therapy as a medical therapy, validated by the numerous world scientific researches, has an anti – bacterial / viral / fungal power and in particular anti inflammatory.
MECHANISM OF ACTION
Inactivation of bacteria, viruses, fungi, yeast and protozoa:
Ozone therapy disrupts the integrity of the bacterial cell envelope through oxidation of the phospholipids and lipoproteins.
In fungi, O3 inhibits cell growth at certain stages.
With viruses, the O3 damages the viral capsid and upsets the reproductive cycle by disrupting the virus-to-cell contact with peroxidation.
The weak enzyme coatings on cells which make them vulnerable to invasion by viruses make them susceptible to oxidation and elimination from the body, which then replaces them with healthy cells.
Stimulation of oxygen metabolism: Ozone therapy causes an increase in the red blood cell glycolysis rate. This leads to the stimulation of 2,3-diphosphoglycerate which leads to an increase in the amount of oxygen released to the tissues.
Ozone activates the Krebs cycle by enhancing oxidative carboxylation of pyruvate, stimulating production of ATP.
It also causes a significant reduction in NADH and helps to oxidize cytochrome C. There is a stimulation of production of enzymes which act as free radical scavengers and cell-wall protectors: glutathione peroxidase, catalase and superoxide dismutase.
Production of prostacyline, a vasodilator, is also induced by O3 [Figure 1].
Activation of the immune system: Ozone administered at a concentration of between 30 and 55 μg/cc causes the greatest increase in the production of interferon and the greatest output of tumor necrosis factor and interleukin-2.
The production of interleukin-2 launches an entire cascade of subsequent immunological reactions.
ADVANTAGES OF OZONE THERAPY
Diabetic complications are attributed to the oxidative stress in the body, O3 was found to activate the antioxidant system affecting the level of glycemia.
Ozone prevented oxidative stress by normalizing the organic peroxide levels by activating superoxide dismutase.[36–37]
Ozone was found to completely inactivate the HIV in vitro, this action of O3 was dose-dependent.
Concentration used for inactivation was found to be non-cytotoxic. The inactivation was owing to the reduction of the HIV p24 core protein.
Ozone was also found to increase the host immunity by increasing the production of cytokine.
In an in vitro study, it was observed that O3 is very effective in reducing the concentrations of Acinetobacter baumannii, Clostridium difficile and methicillin-resistant Staphylococcus aureus in dry as well as wet samples, hence it can be used as a disinfectant.
It’s no secret in the cleaning and disaster restoration industry that ozone is extremely effective at removing odors through molecular oxidation. Lesser known is its efficacy as a disinfectant, for which it has been used effectively in the medical field for many years. A powerful gas capable of high levels of disinfection, ozone can be very effective at killing pathogenic bacteria and fungi, as well as for inactivating viruses. The focus of this article is the use of ozone as a virucide, with emphasis on the SARS-CoV-2, which, according to the International Committee on Taxonomy, is the accurate name for what is commonly referred to as the COVID-19 coronavirus, and is how it will be referenced in this article.
What is a virus?
Quoting the National Institute of Health: “A virus is an infectious agent that occupies a place near the boundary between the living and the nonliving. It is a particle much smaller than a bacterial cell, consisting of a small genome of either DNA or RNA surrounded by a protein coat. Viruses enter host cells and hijack the enzymes and materials of the host cells to make more copies of themselves. Viruses cause a wide variety of diseases in plants and animals, including AIDS, measles, smallpox, and polio”, and of course the various strains of coronavirus, including SARS-CoV-2 .
They can enter the body through the nose, mouth or breaks in the skin. Different viruses infect different types of cells based upon the ability of the virus to both recognize the host cell type and successfully enter the cells. Once inside (infection), virus genome is activated to produce the replication proteins necessary to create new virus particles, and the cycle is repeated. For example, cold and flu viruses will attack cells that line the respiratory or digestive tracts. Norovirus, for example, invades the gastro-intestinal tract. The cells of the lungs and bronchi are targets for SARS-CoV-2.
Viruses can stay active on surfaces for different amounts of time, depending on the virus, the surface type, and the environment. Cold viruses can remain active on surfaces for up to a week, while flu viruses can survive for about 24 hours, and the SARS-CoV-2 virus remains active for about 72 hours. It’s during this time that the virus is quietly adherent to surfaces, waiting to be taken up by a passing host, that restorers have their opportunity to intervene.
Let’s set the record straight in regard to the correct language for destroying viruses before we “put ‘em in the ring” with ozone. Depending on with whom you speak, you’ll hear somebody say they’re “killing the virus”. Other common terms are deactivating and inactivating.
Which is correct?
As we’ve already discussed, viruses are not living organisms in the traditional sense – they are not made of cells, they cannot reproduce without invading a host cell, they do not respond to environmental stimuli, and they have no metabolism. Because a virus is not “alive” in the first place, it therefore cannot be “killed”. References to killed virus in the medical literature refer to a technique where virus are chemically or mechanically inactivated so that they can be used in the production of vaccines or used in research without the possibility of causing infection, or in our case, to disinfect a surface or space. It is in this sense that we are using the term “inactivating”, where we are using ozone to chemically treat a virus so that it cannot infect living cells.
How does ozone inactivate viruses?
To address this question, I reached out to some of the most knowledgeable doctors on the topic of ozone and viruses in the country. Dr. Gérard Sunnen is a medical doctor in New York City, specializing in the uses of ozone in the medical field, ranging from cutting-edge ozone therapy to the use of ozone as a disinfectant. According to Dr. Sunnen. “Ozone has unique disinfectant properties. As a gas, it has a penetration capacity that liquids do not possess. In view of the fact that , SARS-CoV-2, MERS, and previous SARS strains persist on fomites (surfaces) for up to several days, it is suggested that ozone technology be applied to the decontamination of medical and other environments”.
Knowing that something works isn’t enough; let’s look at how ozone works at inactivating viruses. “Typically, viruses are small, independent particles, built of crystals and macromolecules. Unlike bacteria, they multiply only within the host cell. Ozone destroys viruses by diffusing through the protein coat into the nucleic acid core, resulting in damage of the viral RNA. At higher concentrations, ozone destroys the capsid or exterior protein shell by oxidation” explains Dr. Sunnen. Further, “most research efforts on ozone’s virucidal effects have centered upon ozone’s propensity to break apart lipid molecules at sites of multiple bond configuration. Indeed, once the lipid envelope of the virus is fragmented, its DNA or RNA core cannot survive”.
In my quest for further communication with experts in the field, I reached out to a director for the Center for Disease Control (CDC), Dr. Paul Meechan PhD, MPH, RPB, CBSP, SM(NRCM). I asked him his thoughts on ozone as a virucide, especially in regard to SARS-CoV-2. He responded, “Will ozone work- you betcha! Ozone is very effective at inactivating viruses, especially enveloped viruses like the SARS-CoV-2. Within seconds, ozone solubilizes the lipid membrane of the virus. Ozone will inactivate SARS-CoV-2, but you have to know what you’re doing.
How much ozone is required to be effective?
Log reduction is a mathematical term that is used to express the relative number of living microbes or active viruses that are eliminated by disinfection, and corresponds to inactivating 90% of a target microbe with the microbe count being reduced by a factor of 10. Thus, a 2 Log reduction will see a 99% reduction, or microbe reduction by a factor of 100, and so on. The table below shows the chart of Log reduction.
An easy way I remember this scale is that the number of nines is equal to the Log reduction number. For example, 1 Log = 90%, 3 Logs = 99.9, 5 Logs = 99.999, etc.
Depending on the virus targeted, concentration and exposure time varies. Considering the structure of SARS-CoV-2, and how like viruses respond to ozone exposure, it is estimated that as little as 1 ppm concentration for a matter of seconds is sufficient to achieve as much as 4 logs disinfection. A good quality ozone generator should have no problem reaching this concentration within a short period of time.
Ozone level output is key; generators are rated by the grams of ozone they generate per hour (g/hr). To test the time required to achieve 1 ppm concentration, we used RamAir’s OzoGen 16g, which has an output of 16 g/hr. Our laboratory consisted of a 1000 ft.³ space, at 65° F and 14% RH (relative humidity). The generator achieved .5 ppm in 15 seconds, and 1 ppm in < 2 minutes. As ozone generators convert ambient oxygen into ozone by way of molecular fission and fusion, the rate of output slows as the concentration elevates, resulting from a continuous depletion of available O2 molecules in the enclosed space. Therefore, peak ozone generation is directly dependent on the power of the ozone generator, as lesser systems would plateau at a lower ozone concentration. High power ozone generators also have the benefit of achieving effective concentrations more quickly, which allows for greater overall utility and benefit.
David Hart, alongside a select team of doctors and scientists, is spearheading a rigorous testing program to acquire precise data on ozone’s inactivation of specific strains of pathogenic bacteria, fungi and viruses, in regard to concentration and exposure times.
Ozone, having been proven in the lab and in the field to be an extremely effective virucide and full-spectrum antimicrobial, killing pathogenic bacteria and fungi, offers many benefits over alternative ways of disinfecting.
Because it is a gas, it has a penetration capacity that liquids do not possess. An ozone generator never needs to be refilled with solutions, and it doesn’t need to be manually operated; simply set the timer and press the button. The machine goes to work turning the oxygen in the ambient air into powerful, oxidizing ozone. You return after the prescribed period of time, and the disinfection is complete.
It is no surprise that ozone will neutralize coronavirus. Ozone is well known to be a powerful disinfectant. It is especially effective with small pathogens such as viruses and bacteria. Some of the more recent studies have demonstrated that coronavirus can thrive in the air in the form of aerosols breathed from people. Recent research has demonstrated that low levels of ozone gas effectively neutralizes coronavirus.
Ozone is a simple high-energy molecule of three oxygen atoms and will irritate sensitive tissue such as our lungs when ozone concentrations exceed 0.1 parts per million. The good news is that coronavirus is much more sensitive to ozone than our lungs are. “Scientists at Fujita Health University told a news conference they had proven that ozone gas in concentrations of 0.05 to 0.1 parts per million (ppm), levels considered harmless to humans, could kill the virus.”
The important details are the ozone level and the contact time. Coronavirus exposed to ozone concentrations of 0.1 ppm for 10 hours reduced the potency of the virus 90%. Ozone is not a magic bullet, but it is a valuable tool in our arsenal for fighting the virus. It is a safe, comfortable, and effective tool that can provide secondary benefits. The ultraviolet rays of the sun and lightning naturally produce low levels of cleansing ozone. Well-controlled equipment is already available to bring some of the fresh outdoors into our living and working spaces to stand side by side with others in the battle against viruses.
Oxidation Technologies has worked for years to produce safe and effective ozone generating equipment. We specialize in equipment controls to precisely maintain specified ozone levels for commercial applications. We have the equipment and expertise to maintain safe levels of ambient ozone that will greatly reduce the ability of coronavirus to thrive. We would be happy to assist in your efforts to get employees back into the workplace.
Currently, no medicine has demonstrated efficacy in treating the ongoing pandemic COVID-19 caused by SARS-CoV-2 virus. Being a potent oxidant, ozone is lethal against most bacteria and viruses found in water, or on surfaces and aerosols. Ozone has also been successfully used to treat several viral diseases such as Ebola and HIV Hepatitis B and C. Using molecular modeling, this study evaluated the reactivity of ozone toward representative key molecules in the structure of SARS-CoV-2. The results show that ozone is able to attack the proteins and lipids of the virus’s spikes and envelope, particularly the amino acids tryptophan, methionine and cysteine, and the fatty acids, arachidonic acid, linoleic acid, and oleic acid. Ozone also attacks the N-glycopeptides of the spike protein subunits 1 and 2, though at lower reactivity. Disruption of the structure of SARS-CoV-2 could inactivate the virus, suggesting that ozone could be an effective oxidant against COVID-19 virus. If incorrectly applied, ozone is toxic and contact with the respiratory tract must be avoided.
Ozone has been used successfully to inactivate pathogens and viruses in many applications and has a long history of success. Based on this the assumption is made that ozone will also inactivate the SARS-CoV-2 virus. This study uses representative viruses, and molecular modeling to provide that ozone could be an effective oxidant against SARS-CoV-2. Ozone was able to attach the proteins and lipids of the virus destroying the integrity of the virus rendering it unable to cause further infection or reproduction.
This paper was published by the IOA (International Ozone Association). For more papers like this, and full access to this paper, become an IOA member today: