Different foods require different types of packaging. Using carbon dioxide and/or nitrogen in combination with ozone treatment can be used when packaging is to be sealed in air-tight plastic bags. Inert gases remove any oxygen remaining after ozone disinfects microorganisms on surfaces. Ozone in food packaging can help prevent various virus and infections.

Ozone for Treating Process Room Air

Food processing rooms without workers (such as a storage area) can be sprayed with ozone to levels that are effective for their intended purposes. This can be accomplished by removing the contaminated air from the room, treating it with ozone, eliminating excess ozone, and then returning the cleaned air to the processing room. The ceiling of the processing room can be fitted with ozone-producing UV lamps. Compared to the corona discharge technique used to treat large quantities of water, these lamps produce lower concentrations of ozone when turned on.  

Ozone generators must not turned on during human occupancy. The processing room should be fanned a few minutes before workers return to exhaust the last traces of ozone before the workers return. Using this method isn’t practical for odors that develop rapidly during processing or for odors that are heavy or pungent. This procedure can be used to eliminate mild odors as well. Furthermore, airborne mold levels in process rooms can be greatly reduced with this treatment.

As an example, ozone is often used to keep fruit in controlled atmosphere rooms. Summer/fall fruit is preserved in these large rooms so it can be sold in winter/spring after summer stocks have disappeared and prices are higher. Negative pressure, nitrogen gas flooding, cold temperatures (35 °F), and a slight residual of ozone are used in these storage rooms to prevent mold and mildew.

For Plant Wash Down  

“Ozone-wash carts” are designed by many ozone equipment suppliers and produce a pressurized water stream with dissolved ozone in a few parts per million of water. Because dissolved ozone is present in aqueous spray, microorganisms on exposed surfaces will be destroyed by ozone whenever the spray contacts them.

Products do not suffer any adverse effects from the ozonated water. If sprayed with chlorinated and/or peroxygenated sanitizers, they would also have to be disposed of. However, ozone washes do not provide residual protection against microbial growth after cleaning food and container surfaces.

Ozone for Treating Water

There are a variety of sources of water used in food processing plants, including municipal, river and lake water. Ozone can be an effective treatment if the water hasn’t been treated. According to the impurities present in the influent water, the necessary application rates must be determined. As well as flocculating clays, ozone can help chemical compounds adhere to surface waters. Oxidation of dissolved organic compounds can aid in filtering, increasing the number of runs needed to backwash the filter. As treated water enters the food processing plant, ozone can also be used as a disinfectant.

Ozone for Process Water Recycle and Reuse

To properly treat process waters for reuse, it is important to pay attention to the materials the waters contain today. To recycle and reuse process water, appropriate procedures should be followed, which can include one or more of the following steps:

Flocculating agents (as necessary to assist in the removal of organic contaminants and colloidal materials), sedimentation, dissolved air flotation (DAF), filtration, treatment (with ozone) before recycling, etc. Oxygen saturating the water with ozone gives the treated water a greater optical transmittance, making it a significant advantage over untreated water.

Ozone for Waste Water Treatment and Disposal

Food processing plants typically produce high concentrations of organic contaminants in their waste water. Biodegradable wastes are usually suitable for biological waste water treatment because they are easily biodegradable. It requires extensive land areas and a significant amount of time (~ 30 days or more) for completion. Food processors can reduce the amount of energy they add to waste water by using biological treatment.

It is possible to reduce BOD and COD levels using ozone when there is insufficient time for bioprocessing. Various studies have shown that ozone can aid in sludge dewatering, thereby aiding filtration. In biotreatment, effluents can be disinfected with ozone, thereby avoiding chlorination and preventing the formation of chlorinated organic compounds that enter the environment and reach human consumption.

Ozone for Washing Foods

A very clean and sterile water is required for this application. This is not typically a reused water application. Nevertheless, ozone’s oxidative properties allow it to destroy many organic contaminants found in food wash waters, extending the time the wash water can be used before it needs to be disposed of.

Significant cost savings can be achieved by simultaneously reducing water use, chlorine use, and wastewater effluent volume.

Ozone for Storage of Raw Food Products

Based on prior research, the food-specific level of ozone to be used in this application is determined based on the type of food. Washing and packaging (sometimes with air exposure, sometimes not) are the steps involved in preparing foods for consumption. Ozone is often present in the atmosphere where raw food products are stored. To prevent damage to food products, it is important to know the concentration of ozone needed. You can learn more about ozone in food processing here.