Ozone

Ozone as a powerful antimicrobial agent can be used for decontamination of water, produce, equipment, foodcontactsurfaces, and processing environment because it is applicable in the aqueous and gaseous states.

 


The triatomic molecule Ozone has a characteristic pungent odour which can be described as similar to fresh air after a thunderstorm. A small concentration of ozone naturally occurs at the Earth’s surface. Ozone is formed by the action of UV solar radiation (< 240 nm) on molecular oxygen in the stratosphere. A small proportion is transported to the troposphere and about 10 % of the atmospheric ozone is present in the troposphere. For industrial scale ozone can be produced by three different methods: electrical discharge, electrochemical, and UV radiation.

The effects of ozone have been known for more than hundred years. The high oxidising potential makes ozone the strongest disinfection agent available for the contact with foods and water and wastewater treatment. Many investigationsestablished the bactericidal and fungicidal properties. The application of ozone may be advantageouscompared to chlorine because unlikechlorine ozone decomposes quickly and does not generatehazardous residuesbut can evendestroy pesticides and other harmfulorganic substance. The efficiency of ozone is dependent on target microorganism, initial inoculum level, and physiological state of the treated bacteria, ozone delivery method, and type of food. Ozone inactivation of microorganisms is a complex process. Ozone attacks various cell membrane and wall constituents (e.g. unsaturated fats) and cell content constituents (e.g. enzymes, proteins, and nucleic acids). The microorganisms are inactivated by cell wall disruption or disintegration leading to leakage of the cell contents. This action of ozone implies that the microorganisms cannot be resistant against ozone inactivation. Ozonation has been adopted for water treatment and disinfection in France, Germany, the Netherlands, Austria, Switzerland and many other countries. Over the world more than 3000 ozone-based water treatment are installed.

In the food industry ozone applications are related to decontamination of product surfaces, food plant equipment, reuse of waste water, and lowering biological oxygen demand and chemical oxygen demand of food plant waste. Inactivation of contaminated microflora on meat, poultry, eggs, fish, fruits, vegetables, and dry food by ozone was obtained with different success.

 

Figure: Washing of salad with ozonated water (© Karin Hassenberg, ATB, Potsdam, Germany)

 

 

 

 

 

 

 

 

 

 

 


This text was prepared by Antje Fröhling of the Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Department of Quality and Safety of Food and Feed, Potsdam, Germany.

For further questions please refer to: afroehling@atb-potsdam.de


 

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