Ozone: A Natural Sterilizer for Fruit and Vegetables

Both consumers and government have long been concerned about the safety of food, vegetables, fruits and RTE food. It is about the prevention of pathogens and chemical hazards. In the United States and Europe, for example, many restaurants use chlorine to disinfect salad washing water.

But the common chlorine disinfection is also responsible for the large amount of food contaminated with chlorine-related chemicals. To promise safety, the use of chlorine as a means of disinfection is heavily restricted in Europe. As a result, many are turning to a better choice to kill bacteria which is realized by using ozone generators.

Application of Ozonated Water

By dissolving ozone gas into water, ozonated water produced can be safely used to wash fruits, vegetables and RTE foods such as salads. Ozone can often be used in combination with filtration to enhance its effectiveness. Water that comes out of a tap will be pre-injected with ozone. This will maintain a certain ozone concentration in the water.

If chemical disinfectants are still needed as an auxiliary disinfectant, chlorine gas can still be used. But with the use of ozone, there will be less required than it is used as the primary disinfectant.

The use of ozone is mainly in side stream. And a diffuser is required to ensure the mixing of side stream with bulk flume water flow. If needed, to maintain the concentration in the water, the water in the tank can be continuously circulated through the ozone unit.

The concentration of ozonated water for cleaning a sink is 0.05-0.15ppm. A concentration of 1-3 ppm is used for spray washing applications. In a spray washing application, ozone in different positions have different concentrations. 

The concentration of the ozone gas injected into the water may be 3 ppm. But when transmitted in the pipeline, concentration at the nozzle is less than 3 ppm. An usual concentration is about 1.5-2.0 ppm. When the ozonated water is ejected, due to the lower air pressure, part of the ozone gas will be precipitated out of the water. There will be an ozone concentration at about 0.5-1.0 ppm in the water in direct contact with the food surface.

Benefits of Ozone for Fruit and Vegetable Disinfection

The following are the benefits of using ozone gas for fruit and vegetable disinfection:

• A stronger disinfection effect than chlorine, chlorine dioxide and peracetic acid
• Effective against a variety of pathogens, including bacteria, viruses, cryptosporidium and giardia
• Has a half-life less than half an hour and breaks down quickly into oxygen
• No production of any harmful byproducts similar to that in water chlorination
• Effectively prevent salads and other RTE foods from being contaminated by disinfection byproducts
• Realize the safe discharge of washing water

Kill Pathogens with an Ozone Spray Washing Application

The following are the pathogens than can be reduced in number when an ozone spray washing application is used:

Ozone’s Benefits for Washing Fruit and Vegetables

Complete eliminate THM and other chlorination byproducts: The use of ozone does not produce any harmful chlorination products.

It is applicable to the situation that there are strict restrictions on the residues of chlorinated by-products in food in the European Union.

Effective reduction of pesticide residues: Ozone can effectively break down pesticide residues on food with its chemical oxidation of ozone and promote further biodegradation.

Enhance food appearance and taste: Ozone has been shown to improve the appearance and taste of salads as well as preventing the spread of food borne pathogens.

Extend shelf life: Food spoilage is due to the presence of bacteria and viruses. Ozone’s inhibition effect provides food with a longer shelf life and makes long distances transportation possible.

Reduce water consumption and promote water circulation: After oxidation, water can be used for a longer time than after chlorination. In addition to the ozone’s disinfection effect, organic pollutants that may be present in a sink can also be oxidized and removed.