How quickly does ozone kill bacteria?

Posted by Joel Leusink on November 10, 2011 under Ozone food | Be the First to Comment

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.

E.coli Reduction With Ozone

Posted by Joel Leusink on March 30, 2010 under Food Industry | Read the First Comment

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

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:

• Ozone Use in Food Processing
• Ozone Use in Extending Shelf life in Food
• Ozone Effect on Bacteria
• Ozone removes E.coli O157:h7
• E.coli O157:57 Research