Posted by Joel Leusink on February 9, 2012 under Food Industry | 
Ozone use for the inactivation of listeria
Listeria is a common term to refer to a specific strain of bacteria species. There are seven (7) known species of Listeria. The specific species L. monocytogenes is the cause of Listeriosis, a serious infection caused by eating food contaminated with this strain of bacteria. This disease can be deadly and will pose a greater risk to those with weakened immune system. Both L. monocytogenes, and Liseteriosis, are commonly known only as Listeria, and Listeria illness.
Listeria is found in soils, this can lead to fruit and vegetable contamination. Listeria can also be found in all types of meat products, milk, and eggs. Higher risk foods are any uncooked or undercooked foods, unpasteurized milk, raw vegetables, and some ready-to-eat foods.
Click here to learn more about Listeria from the CDC (Center for Disease Control and Prevention).
Ozone can be used for the reduction, or elimination of L. monocytogenes on food products. Since achieving GRAS approval for the use of ozone for direct contact with food in 2001 the use of ozone for the elimination of L. monocytogenes has increased significantly.
To eliminate Listeria or any other bacteria with ozone successful implementation of ozone is necessary. While every application is different, there are a few fundamentals that will apply in most applications.
Implementation of Ozone
Aqueous Ozone
The most common method of using ozone for pathogen reduction is by dissolving ozone into water. Aqueous ozone is very stable, safe, and easy to manage. Typically, ozone is dissolved into water using an Ozone Injection System and then sprayed onto the surface requiring disinfection. This surface may be a hard equipment surface, or the surface of a food product.
In 2000, the Journal of Food Science published a paper by Kim & Yousef showing the effect of dissolved ozone in a batch reactor on Listeria monocytogenes. Dissolved ozone at 0.4 and 0.8 ppm inactivated 4.6 and 5.7 log CFU/ml within 30 seconds. Additional tests were run at higher dissolved ozone levels. Higher dissolved ozone levels did show faster (immediate) inactivation of Listeria monocytogenes.
Dissolved ozone can be sprayed on food and produce using spray bars, or other spraying methods. Conveyers work well to allow the sufficient contact time, and offer full coverage of the aqueous ozone. It is important that all of the produce is contacted by the aqueous ozone to achieve desired antimicrobial intervention. Contact times can be varied by altering conveyer speeds, spray tip design, and spray bar design/quantity. If water is already used in an application to wash produce it is very simple to add ozone to this water and achieve an antimicrobial intervention step without any major changes to the current processes.
Gaseous ozone
The use of gaseous ozone for the elimination of pathogens is less common. There is 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 L. monocytogenes; however, more research is necessary to determine the effectiveness of ozone within different variables.
Produce in need of disinfection can be placed in chambers, rooms, or even cargo containers for ozone treatment. A sealed area that can contain the produce and ozone gas while maintaining human safety will work. It is necessary to assure sufficient air movement past each piece of produce. Ozone levels from 1.0 — 100 ppm are used in this application with contact times from 20 minutes to 10 hours. For more information on the potential of using gaseous ozone in your application contact our application engineers today.
Click here for more information and to view ozone research papers on this topic
Posted by Joel Leusink on December 14, 2011 under Ozone News |
New way found to fend off hospital infections
Read full article HERE
Researchers in Canada say their new disinfection system may change the way hospital rooms, and perhaps hotel rooms, worldwide are cleaned.
Dr. Dick Zoutman, chief of staff at Quinte Health Care, and Dr. Michael Shannon of Medizone International at laboratories in Innovation Park, Queen’s University, Kingston, Ontario, said the new disinfection technology also killed bed bugs.
The new technology involves pumping a mixture of Medizone-specific ozone and hydrogen peroxide gas into a room to sterilize everything — including floors, walls, drapes, mattresses, chairs and other surfaces. It is far more effective in killing bacteria than wiping down a room, Zoutman said.
Read more: http://www.upi.com/Health_News/2011/12/12/New-way-found-to-fend-off-hospital-infections/UPI-94161323748255/#ixzz1gVyoQ46D
Learn more about how ozone kills bacteria HERE
Posted by Joel Leusink on November 10, 2011 under Ozone food |
Frequently we are asked how quickly ozone kills or inactivates bacteria within processes. This is an important factor to understand when using ozone for food processing, wastewater disinfection, and other antimicrobial intervention applications.
To see how ozone kills bacteria click HERE
We performed research and wrote a paper on the effect of various levels of ozone on generic E.coli. This research indicated water containing ozone at levels of 2.0 ppm or higher could kill bacteria at sufficient levels within 1 second of contact time. This research also showed that higher levels of ozone dissolved into water did not achieve any better bacteria reduction, or faster bacteria reduction. See image below:
Click on image for a larger version
This chart shows logs of generic E.coli on the left (Y axis). This shows the pork product started with 6-7 logs of bacteria. This was reduced to a level of about 2-3 log of bacteria. An average reduction of 4 logs of bacteria using ozone.
On the bottom of this chart the exposure of aqueous ozone on the pork product is shown. This shows that at ozone levels of 2.0 ppm or greater only 1 second of contact time will achieve the 4 log reduction of bacteria, with no real advantage of longer contact times.
The great results of this research provide money saving information for many applications. This shows that lower ozone levels (2.0 ppm) can be used with very short contact times. This may reduce overall water use in applications, and lower energy costs required for ozone production.
If you have questions on this research or any of our other research please contact our application engineers today.
Posted by Joel Leusink on May 29, 2011 under Wastewater Treatment |
Wastewater Disinfection
The use of ozone for wastewater disinfection has been growing in popularity due to strict regulations on fecal coliform and other pathogens. As chemical costs rise, ozone becomes a more cost effective solution for wastewater disinfection. Ozone can be produced on site using oxygen from the ambient air. Only electrical power is required for operation.
When discharge limits on pathogens are lowered, the natural solution is to add additional chemicals to meet these new limits. Adding more chemicals to a wastewater stream effluent for disinfection may seem like an easy solution at first; however, in many cases these chemicals must then be removed from the effluent wastewater prior to discharge due to limits on these chemicals. For example, if chlorine is used for the reduction of E.coli the chlorine must be removed using de-chlorination prior to wastewater discharge. If 20% more chlorine is required to meet the new wastewater discharge limits, 20% de-chlorination must also be applied to this water. Over time, these costs can really add up.
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Ozone’s reactive properties allow it to quickly kill bacteria. In fact, ozone is ten times stronger than chlorine as a disinfectant. |
Ozone is a green solution
Ozone is a green solution to wastewater disinfection. Ozone is produced on site and is all natural, formed from only oxygen. No by-products or waste products are formed in the creation of ozone.
- The use of ozone eliminates the need to transport chemicals to the site.
- Ozone is produced on-site from air and electricity, all renewable resources.
- Ozone is a completely renewable resource.
- Potential hazardous storage of chemical is removed with ozone use.
- After ozone is dissolved into water, ozone reverts to oxygen leaving no residual in the water.
The Ozone Advantage
Using ozone for wastewater disinfection offers many advantages in cost savings, space savings, labor savings, and cleaner water. More and more wastewater plants are making the switch to ozone use to capitalize on these advantages.
- Ozone leaves no residual, so only ozone injection is necessary. No second chemical for quenching is necessary.
- Ozone is produced on site from renewable resources and requires no chemical storage.
- Ozone is clean, safe, and reliable, taking up less space, and less equipment than many chemical treatment/storage systems.
- Using ozone saves money by eliminating on-going chemical costs.
- Ozone will destroy all bacteria without a preference to one type of organism. Ozone will also remove some BOD, COD, and many other contaminates in the waste water stream. Many customers comment on the clarity of the water after switching to ozone.
- Ozone is effective on wastewater with TDS and TSS levels that may not be acceptable with UV disinfection. Therefore, filtration will not be necessary for ozone use in many wastewater applications.
- Fewer secondary by-products like tri-halomethones (THM’s) are formed with the use of ozone.
Secondary Benefits of Ozone Use
The use of ozone in wastewater disinfection has gained popularity in recent years due to the secondary effects that ozone may offer in some applications. These secondary benefits have helped make ozone a cost effective alternative, and a necessary alternative in some applications.
- Color removal with ozone is a common use of ozone. While ozone is used primarily for disinfection a secondary effect is color removal of the effluent water stream. Using ozone for disinfection may offer the elimination of a second technology used for color removal.
- Oxidation of odor causing compounds in the water may also be a secondary effect of ozone use in wastewater. By eliminating these compounds odor control may be completed during the disinfection process.
- Micro-pollutant removal from water using ozone is gaining interest at a rapid rate. Using ozone for wastewater disinfection may offer the secondary benefit of micro-pollutant removal and eliminate the need to add processes in the treatment stream with future regulations.
- Suspended solids may also be removed or reduced with the use of ozone. Ozone is commonly used for the removal of suspended solids in drinking water, these same effects are achievable in wastewater.
History of Ozone and Wastewater Disinfection
Ozone used for wastewater disinfection became popular early on when the widespread use of ozone gained popularity in the 1970′s and 1980′s. Due to lack of equipment reliability and rising costs, the use of ozone almost complete disappeared from this application. In recent years however, ozone is getting another chance in many locations across the USA and Europe. This is partly due to improvement in equipment reliability and lower cost; however, the main reason for this revival is the secondary benefits that ozone offers along with the increased costs of chemicals creating an economic advantage. See the timeline.
This page on our website
Posted by Joel Leusink on May 11, 2011 under Ozone food |
The following paper can now be found on our website.
Antimicrobial Effects of Ozonated Water Against Generic E.coli on Swine Intestines Varying Ozone Concentrations and Exposure Times
Abstract:
Swine intestines harvested then turned inside-out and washed with cold water to remove all visible contaminants were tested to have a generic E.coli load of 6 to 7.5 logs per gram of tissue. Samples of these tissues were treated with ozonated water at various concentrations for various lengths of time up to a total of 30 seconds. It was determined that concentrations below 1 ppm had no significant anti-E.coli effects at any of the exposure times tested. At 1 ppm and above significant kills were achieved with a 1 second exposure time. At 1 ppm and up to 2.5 ppm a 15 second exposure time was needed to achieve the greatest E.coli kill, and at 3 ppm and above a 1 second exposure time was all that was needed to achieve the greatest E-coli kill.
Full Paper HERE
This paper is very exciting as it shows the concentration of ozone in water and the contact time necessary to achieve E.coli reduction. This papers shows that 2.0 ppm of dissolved ozone for only 1 second of contact time achieves a 3 log reduction of E.coli bacteria. This new data is extremely useful in understanding the effectiveness of ozone use in spray applications where contact time is very short.
Ozone Solutions has a full collection of research on our website here.
For more information on ozone use for food processing click here.
Posted by Joel Leusink on May 3, 2011 under Ozone food |
News report:
Taylor Farms Pacific, Inc., a California-based food supplier for six retail chain stores, has announced the recall of grape tomatoes produced by a grower who said the vegetables might be contaminated with salmonella.
The recall applies to 29 brand-packaged salads sold at Albertson’s, Raley’s, Sam’s Club, Savemart, Signature Cafe and Wal-Mart, the company said in a statement Monday. The affected products have expiration dates ranging from April 27 to May 9, according to the news release.
Link to full article
This is another great application where aqueous ozone quite possibly could have prevented a costly recall. Aqueous ozone is commonly used directly on food products during washing or packaging as an antimicrobial intervention step. While ozone cannot fix all microbiological problems, reading stories like this does make you wonder what role we could have played.
Ozone use in food processing
Posted by Joel Leusink on March 31, 2011 under Food Industry, Ozone News |
Ozone is commonly used for the reduction, or elimination of E.coli on food products. Since achievingGRAS approval for the use of ozone for direct contact with food in 2001 the use of ozone for the elimination of E.coli has increased significantly. The specific strain of E.coli most frequently targeted is E.coli O157:H7.
We have assembled some research on the use of ozone specifically for E.coli O157:H7. This research is linked HERE, we have provided the white paper title, author, and abstract for your review, along with a link to the full paper for your use.
If you have any further questions on the use of ozone for the inactivation of E.coli O157:H7, or any other pathogen, please contact our application engineers today.
Posted by Joel Leusink on March 30, 2010 under Food Industry |
Antimicrobial effect of Ozonated water against E.coli
Recently we performed some research using ozone as an antimicrobial agent against E.coli. Specifically this research was based on determining what level of ozone (in ppm) was necessary for what period of time ( in seconds) was necessary for adequate E.coli reduction.
The ozone levels and times shown in the chart below were used in this test. The reduction of bacteria is shown in the table for the ozone concentration and contact time used.
Table Shows Log Reduction of E.coli with Ozone
|
1 Second |
7 Seconds |
15 Seconds |
30 Seconds |
| 1 PPM |
1.4 |
2.7 |
4.7 |
4.7 |
| 1.5 PPM |
1.6 |
2.8 |
3.1 |
3.1 |
| 2 PPM |
3.5 |
3.6 |
3.8 |
3.8 |
| 2.5 PPM |
3.1 |
3.2 |
3.6 |
3.7 |
| 3 PPM |
3.5 |
3.7 |
3.7 |
3.7 |
| 3.7 PPM |
3.6 |
3.8 |
3.9 |
4.2 |
| 4.4 PPM |
4.2 |
4.9 |
4.6 |
4.8 |
This chart was generated from an average of 3 samples tested. The full results are available online in the paper below.
Click HERE to read this entire paper
This test was very successful in that it proved that only 2.o PPM of ozone for 1 second of contact time achieves similar results to much higher ozone concentrations for longer contact times. This may allow for lower water flows to be used with smaller ozone generation systems. This may be a net energy savings for many processing plants currently using dissolved ozone as an antimicrobial intervention.
While this test used dissolved ozone to inactivate E.coli on pork meat it is important to note that ozone can destroy any bacteria on any surface. Call us today to find if ozone is a possible intervention in your current application.
More information on ozone and bacteria reduction can be found at the links below:
Posted by Joel Leusink on March 28, 2010 under Food Industry |
Below is a computer generated illustration of how ozone kills healthy bacteria.
- A healthy bacillus bacterial cell (waiting to ruin your day).
- Zooming in closer, Ozone (light green) comes into contact with the cell wall. The cell wall is vital to the bacteria because it ensures the organism can maintain its shape.
- As ozone molecules make contact with the cell wall, a reaction called an oxidative burst occurs which literally creates a tiny hole in the cell wall.
- A newly created hole in the cell wall has injured the bacterium.
- The bacterium begins to loose its shape while ozone molecules continue creating holes in the cell wall.
- After thousands of ozone collisions over only a few seconds, the bacterial wall can no longer maintain its shape and the cell dies.
Note: bacteria cannot build an immunity to ozone due to the oxidation that occurs on the cell wall.
For more bacteria reduction information follow the links below:
